delivered the opinion of the Court.

When this litigation was first before us we recognized the existence of a federal “common law” which could give rise to a claim for abatement of a nuisance caused by interstate water pollution. Illinois v. Milwaukee, 406 U. S. 91 (1972). Subsequent to our decision, Congress enacted the Federal Water Pollution Control Act Amendments of 1972. We granted cer-*308tiorari to consider the effect of this legislation on the previously recognized cause of action. 445 U. S. 926.

I

Petitioners, the city of Milwaukee, the Sewerage Commission of the city of Milwaukee, and the Metropolitan Sewerage Commission of the County of Milwaukee, are municipal corporations organized under the laws of Wisconsin. Together they construct, operate, and maintain sewer facilities serving Milwaukee County, an area of some 420 square miles with a population of over one million people.1 The facilities consist of a series of sewer systems and two sewage treatment plants located on the shores of Lake Michigan 25 and 39 miles from the Illinois border, respectively. The sewer systems are of both the “separated” and “combined” variety. A separated sewer system carries only sewage for treatment; a combined sewer system gathers both sewage and storm water runoff and transports them in the same conduits for treatment. On occasion, particularly after a spell of wet weather, overflows occur in the system which result in the discharge of sewage *309directly into Lake Michigan or tributaries leading into Lake Michigan.2 The overflows occur at discrete discharge points throughout the system.

Respondent Illinois complains that these discharges, as well as the inadequate treatment of sewage at the two treatment plants, constitute a threat to the health of its citizens. Pathogens, disease-causing viruses and bacteria, are allegedly discharged into the lake with the overflows and inadequately treated sewage and then transported by lake currents to Illinois waters. Illinois also alleges that nutrients in the sewage accelerate the eutrophication, or aging, of the lake.3 Respondent Michigan intervened on this issue only.

Illinois’ claim was first brought to this Court when Illinois sought leave to file a complaint under our original jurisdiction. Illinois v. Milwaukee, supra. We declined to exercise original jurisdiction because the dispute was not between two States, and Illinois had available an action in federal district court. The Court reasoned that federal law applied to the dispute, one between a sovereign State and political subdivisions of another State concerning pollution of interstate waters, but that the various laws which Congress had enacted “touching interstate waters” were “not necessarily the only federal remedies available.” Id., at 101, 103. Illinois could appeal to federal common law to abate a public nuisance in *310interstate or navigable waters. The Court recognized, however, that:

“It may happen that new federal laws and new federal regulations may in time pre-empt the field of federal common law of nuisance. But until that time comes to pass, federal courts will be empowered to appraise the equities of the suits alleging creation of a public nuisance by water pollution.” Id., at 107.

On May 19, 1972, Illinois filed a complaint in the United States District Court for the Northern District of Illinois, seeking abatement, under federal common law, of the pub-blic nuisance petitioners were allegedly creating by their discharges.4

Five months later Congress, recognizing that “the Federal water pollution control program . . . has been inadequate in every vital aspect,” S. Rep. No. 92-414, p. 7 (1971), 2 Legislative History of the Water Pollution Control Act Amendments of 1972 (Committee Print compiled for the Senate Committee on Public Works by the Library of Congress), Ser. No. 93-1, p. 1425 (1973) (hereinafter Leg. Hist.), passed the Federal Water Pollution Control Act Amendments of 1972, Pub. L. 92-500, 86 Stat. 816. The Amendments established a new system of regulation under which it is illegal for anyone to discharge pollutants into the Nation’s waters except pur*311suant to a permit. §§ 301, 402 of the Act, 33 U. S. C. §§ 1311, 1342 (1976 ed. and Supp. III). To the extent that the Environmental Protection Agency, charged with administering the Act, has promulgated regulations establishing specific effluent limitations, those limitations are incorporated as conditions of the permit. See generally EPA v. State Water Resources Control Board, 426 U. S. 200 (1976). Permits are issued either by the EPA or a qualifying state agency. Petitioners operated their sewer systems and discharged effluent under permits issued by the Wisconsin Department of Natural Resources (DNR), which had duly qualified under § 402 (b) of the Act, 33 U. S. C. § 1342 (b) (1976 ed. and Supp. Ill), as a permit-granting agency under the superintendence of the EPA. See EPA v. State Water Resources Control Board, supra, at 208. Petitioners did not fully comply with the requirements of the permits and, as contemplated by the Act, §402 (b)(7), 33 U. S. C. § 1342 (b)(7), see Wis. Stat. Ann. § 147.29 (West 1974), the state agency brought an enforcement action in state court. On May 25,1977, the state court entered a judgment requiring discharges from the treatment plants to meet the effluent limitations set forth in the permits and establishing a detailed timetable for the completion of planning and additional construction to control sewage overflows.

Trial on Illinois’ claim commenced on January 11, 1977. On July 29 the District Court rendered a decision finding that respondents had proved the existence of a nuisance under federal common law, both in the discharge of inadequately treated sewage from petitioners’ plants and in the discharge of untreated sewage from sewer overflows, The court ordered petitioners to eliminate all overflows and to achieve specified effluent limitations on treated sewage. App. to Pet. for Cert. F-25 — F-26. A judgment order entered on November 15 specified a construction timetable for the completion of detention facilities to eliminate overflows. Separated sewer overflows are to be completely eliminated by 1986; combined *312sewer overflows by 1989. The detention facilities to be constructed must be large enough to permit full treatment of water from any storm up to the largest storm on record for the Milwaukee area. Id., at D-l. Both the aspects of the decision concerning overflows and concerning effluent limitations, with the exception of the effluent limitation for phosphorus, went considerably beyond the terms of petitioners’ previously issued permits and the enforcement order of the state court.

On appeal, the Court of Appeals for the Seventh Circuit affirmed in part and reversed in part. 599 F. 2d 151. The court ruled that the 1972 Amendments had not pre-empted the federal common law of nuisance, but that “[i]n applying the federal common law of nuisance in a water pollution case, a court should not ignore the Act but should look to its policies and principles for guidance.” Id., at 164. The court reversed the District Court insofar as the effluent limitations it imposed on treated sewage were more stringent than those in the permits and applicable EPA regulations. The order to eliminate all overflows, however, and the construction schedule designed to achieve this goal, were upheld.5

II

Federal courts, unlike state courts, are not general common-law courts and do not possess a general power to develop and apply their own rules of decision. Erie R. Co. v. Tompkins, 304 U. S. 64, 78 (1938); United States v. Hudson & Goodwin, 7 Cranch 32 (1812). The enactment of a federal rule in an *313area of national concern, and the decision whether to displace state law in doing so, is generally made not by the federal judiciary, purposefully insulated from democratic pressures, but by the people through their elected representatives in Congress. Wallis v. Pan American Petroleum Corp., 384 U. S. 63, 68 (1966).6 Erie recognized as much in ruling that a federal court could not generally apply a federal rule of decision, despite -the existence of jurisdiction, in the absence of an applicable Act of Congress.

When Congress has not spoken to a particular issue, however, and when there exists a “significant conflict between some federal policy or interest and the use of state law,” Wallis, supra, at 68,7 the Court has found it necessary, in a “few and restricted” instances, Wheeldin v. Wheeler, 373 U. S. 647, 651 (1963), to develop federal common law. See, e. g., Clearfield Trust Co. v. United States, 318 U. S. 363, 367 (1943). Nothing in this process suggests that courts are better suited to develop national policy in areas governed by federal common law than they are in other areas, or that the usual and important concerns of an appropriate division of functions between the Congress and the federal judiciary are inapplicable. See TV A v. Hill, 437 U. S. 153, 194 (1978); Diamond v. Chakrabarty, 447 U. S. 303, 317 (1980); United States v. Gilman, 347 U. S. 507, 511-513 (1954). We have always recognized that federal common law is “subject to the paramount authority of Congress.” New Jersey v. New *314York, 283 U. S. 336, 348 (1931). It is resorted to “[i]n absence of an applicable Act of Congress,” Clearfield Trust, supra, at 367, and because the Court is compelled to consider federal questions “which cannot be answered from federal statutes alone,” D’Oench, Duhme Co. v. FDIC, 315 U. S. 447, 469 (1942) (Jackson, J., concurring). See also Board of Commissioners v. United States, 308 U. S. 343, 349 (1939); United States v. Little Lake Misere Land Co., 412 U. S. 580, 594 (1973); Miree v. DeKalb County, 433 U. S. 25, 35 (1977) (Burger, C. J., concurring in judgment). Federal common law is a “necessary expedient^” Committee for Consideration of Jones Falls Sewage System v. Train, 539 F. 2d 1006, 1008 (CA4 1976) (en banc), and when Congress addresses a question previously governed by a decision, rested on federal common law the need for such an unusual exercise of lawmaking by federal courts disappears. This was pointedly recognized in Illinois v. Milwaukee itself, 406 U. S., at 107 (“new federal laws and new federal regulations may in time pre-empt the field of federal common law of nuisance”), and in the lower court decision extensively relied upon in that case, Texas v. Pankey, 441 F. 2d 236, 241 (CA10 1971) (federal common law applies “[u]ntil the field has been made the subject of comprehensive legislation or authorized administrative standards”) (quoted in Illinois v. Milwaukee, supra, at 107, n. 9).

In Arizona v. California, 373 U. S. 546 (1963), for example, the Court declined to apply the federal common-law doctrine of equitable apportionment it had developed in dealing with interstate water disputes because Congress, in the view of a majority, had addressed the question:

“It is true that the Court has used the doctrine of equitable apportionment to decide river controversies between States. But in those cases Congress had not made any statutory apportionment. In this case, we have decided that Congress has provided its own method for allocat*315ing among the Lower Basin States the mainstream water to which they are entitled under the Compact. Where Congress has so exercised its constitutional power over waters, courts have no power to substitute their own notions of an ‘equitable apportionment’ for the apportionment chosen by Congress.” Id., at 565-566.

In Mobil Oil Corp. v. Higginbotham, 436 U. S. 618 (1978), the Court refused to provide damages for “loss of society” under the general maritime law when Congress had not provided such damages in the Death on the High Seas Act:

“We realize that, because Congress has never enacted a comprehensive maritime code, admiralty courts have often been called upon to supplement maritime statutes. The Death on the High Seas Act, however, announces Congress’ considered judgment on such issues as the beneficiaries, the limitations period, contributory negligence, survival, and damages. . . . The Act does not address every issue of wrongful-death law, . . . but when it does speak directly to a question, the courts are not free to ‘supplement’ Congress’ answer so thoroughly that the Act becomes meaningless.” Id., at 625.

Thus the question was whether the legislative scheme “spoke directly to a question” — in that case the question of damages — not whether Congress had affirmatively proscribed the use of federal common law. Our “commitment to the separation of powers is too fundamental” to continue to rely on federal common law “by judicially decreeing what accords with ‘common sense • and the public weal’ ” when Congress has addressed the problem. TV A v. Hill, supra, at 195.8

*316Contrary to the suggestions of respondents, the appropriate analysis in determining if federal statutory law governs a question previously the subject of federal common law is not the same as that employed in deciding if federal law pre-empts state law. In considering the latter question “ 'we start with the assumption that the historic police powers of the States were not to be superseded by the Federal Act unless that was the clear and manifest purpose of Congress.’ ” Jones v. Rath Packing Co., 430 U. S. 519, 525 (1977) (quoting Rice v. Santa Fe Elevator Corp., 331 U. S. 218, 230 (1947)). While we have not hesitated to find pre-emption of state law, whether express or implied, when Congress has so indicated, see Ray v. Atlantic Richfield Co., 435 U. S. 151, 157 (1978), or when enforcement of state regulations would impair “federal superintendence of the field,” Florida Lime & Avocado Growers, Inc. v. Paul, 373 U. S. 132, 142 (1963), our analysis has included “due regard for the presuppositions of our embracing federal system, including the principle of diffusion of power not as a matter of doctrinaire localism but as a promoter of democracy.” San Diego Building Trades Council v. Garmon, 359 U. S. 236, 243 (1959). Such concerns are not implicated in the same fashion when the question is whether federal stat*317utory or federal common law governs, and accordingly the same sort of evidence of a clear and manifest purpose is not required. Indeed, as noted, in cases such as the present “we start with the assumption” that it is for Congress, not federal courts, to articulate the appropriate standards to be applied as a matter of federal law.9

Ill

We conclude that, at least so far as concerns the claims of respondents, Congress has not left the formulation of appropriate federal standards to the courts through application of often vague and indeterminate nuisance concepts and maxims of equity jurisprudence, but rather has occupied the field through the establishment of a comprehensive regulatory program supervised by an expert administrative agency. The 1972 Amendments to the Federal Water Pollution Control Act were not merely another law “touching interstate waters” of the sort surveyed in Illinois v. Milwaukee, 406 U. S., at 101-103, and found inadequate to supplant federal common law. Rather, the Amendments were viewed by Congress as a “total restructuring” and “complete rewriting” of the existing water pollution legislation considered in that case. 1 Leg. Hist. 350-351 (remarks of Chairman Blatnik of the House Committee which drafted the House version of the Amendments) ; id., at 359-360 (remarks of Rep. Jones). See S. Rep. No. 92-414, p. 95 (. 1971), 2 Leg. Hist. 1511; id., at 1271 (remarks of Chairman Randolph of the Senate Committee which drafted the Senate version of the Amendments); see also EPA *318v. State Water Resources Control Board, 426 U. S., at 202-203.10 Congress’ intent in enacting the Amendments was clearly to establish an all-encompassing program of water pollution regulation. Every point source discharge11 is prohibited unless covered by a permit, which directly subjects the discharger to the administrative apparatus established by Congress to achieve its goals. The “major purpose” of the Amendments was “to establish a comprehensive long-range policy for the elimination of water pollution.” S. Rep. No. 92-414, at 95, 2 Leg. Hist. 1511 (emphasis supplied). No Congressman’s remarks on the legislation were complete without reference to the “comprehensive” nature of the Amendments. A House sponsor described the bill as “the most comprehensive and far-reaching water pollution bill we have ever drafted,” 1 Leg. Hist. 369 (Rep. Mizell), and Senator Randolph, Chairman of the responsible Committee in the Senate, stated: “It is perhaps the most comprehensive legislation ever developed in its field. It is perhaps the most comprehensive legislation that the Congress of the United States has ever developed in this particular field of the environment.” 2 id., at 1269.12 This Court was *319obviously correct when it described the 1972 Amendments as establishing “a comprehensive program for controlling and abating water pollution.” Train v. City of New York, 420 U. S. 35, 37 (1975).13 The establishment of such a self-consciously comprehensive program by Congress, which certainly did not exist when Illinois v. Milwaukee was decided, strongly suggests that there is no room for courts to attempt to improve on that program with federal common law. See Texas v. Pankey, 441 F. 2d, at 241.14

Turning to the particular claims involved in this case, the action of Congress in supplanting the federal common law is perhaps clearest when the question of effluent limitations for discharges from the two treatment plants is considered. The duly issued permits under which the city Commission discharges treated sewage from the Jones Island and South Shore treatment plants incorporate, as required by the Act, see § 402 (b)(1), 33 U. S. C. § 1342 (b)(1) (1976 ed. and Supp. *320Ill), the specific effluent limitations established by EPA regulations pursuant to § 301 of the Act, 33 U. S. C. § 1311 (1976 ed. and Supp. III). App. 371-394, 395-424; see 40 CFR § 133.102 (1980). There is thus no question that the problem of effluent limitations has been thoroughly addressed through the administrative scheme established by Congress, as contemplated by Congress. This being so there is no basis for a federal court to impose more stringent limitations than those imposed under the regulatory regime by reference to federal common law, as the District Court did in this case. The Court of Appeals, we believe, also erred in stating:

“Neither the minimum effluent limitations prescribed by EPA pursuant to the provisions of the Act nor the effluent limitations imposed by the Wisconsin agency under the National Pollutant Discharge Elimination System limit a federal court’s authority to require compliance with more stringent limitations under the federal common law.” 599 F. 2d, at 173.

Federal courts lack authority to impose more stringent effluent limitations under federal common law than those imposed by the agency charged by Congress with administering this comprehensive scheme.

The overflows do not present a different case. They are point source discharges and, under the Act, are prohibited unless subject to a duly issued permit. As with the discharge of treated sewage, the overflows, through the permit procedure of the Act, are referred to expert administrative agencies for control. All three of the permits issued to petitioners explicitly address the problem of overflows. The Jones Island and South Shore permits, in addition to covering discharges from the treatment plants, also cover overflows from various lines leading to the plants. As issued on December 24, 1974, these permits require the city Commission “to initiate a program leading to the elimination or control of all discharge overflow and/or bypass points in the [Jones Island or South *321Shore, respectively] Collector System ... to assure attainment of all applicable Water Quality Standards.” App. 378-379, 416. The specific discharge points are identified. The Commission was required to submit a detailed plan to DNR designed to achieve these objectives, including alternative engineering solutions and cost estimates, file a report on an attached form for all overflows that do occur, install monitoring devices on selected overflows discharge points, and file more detailed quarterly reports on the overflows from those points. The Commission was also required to complete “facilities planning” for the combined sewer area. “The facilities planning elements include a feasibility study, cost-effectiveness analysis and environmental assessment for elimination or control of the discharges from the combined sewers.” Quarterly progress reports on this planning are required. Id., at 379. A permit issued to the city on December 18, 1974, covers discharges “from sanitary sewer crossovers, combined sewer crossovers and combined sewer overflows.” Id., at 425. Again the discharge points are specifically identified. As to separated sewers, the city “is required to initiate a program leading to the elimination of the sanitary sewer crossovers (gravity) and the electrically operated relief pumps . . . .” Id., at 438. A detailed plan to achieve this objective must be submitted, again with alternative engineering solutions and cost estimates, any overflows must be reported to DNR on a specified form, and monitoring devices are required to be installed on selected points to provide more detailed quarterly reports. As to the combined sewers, the city “is required to initiate a program leading to the attainment of control of overflows from the city’s combined sewer system . . . .” Id., at 443. The city is required to cooperate with and assist the city Commission in facilities planning for combined sewers, see supra, this page, submit quarterly progress reports to DNR, file reports on all discharges, and install monitoring devices on selected discharge points to provide more detailed quar*322terly reports “until the discharges are eliminated or controlled.” App. 444.15

The enforcement action brought by the DNR in state court resulted in a judgment requiring “ [elimination of any bypassing or overflowing which occurs within the sewerage systems under dry weather by not later than July 1, 1982.” Id., at 465. Wet weather overflows from separated sewers were to be subject to a coordinated effort by the Commissions resulting in correction of the problem by July 1, 1986, pursuant to a plan submitted to the DNR. Id., at 469-471. As to the combined sewer overflows, the Commissions were required to accomplish an abatement project, with design work completed by July 1, 1981, and construction by July 1, 1993. Annual progress reports were required to be submitted to the DNR. Id., at 471-472.

It is quite clear from the foregoing that the state agency *323duly authorized by the EPA to issue discharge permits under ^the Act has addressed the problem of overflows from petitioners’ sewer system. The agency imposed the conditions it considered best suited to further the goals of the Act, and provided for detailed progress reports so that it could continually monitor the situation. Enforcement action considered appropriate by the state agency was brought, as contemplated by the Act, again specifically addressed to the overflow problem. There is no “interstice” here to be filled by federal common law: overflows are covered by the Act and have been addressed by the regulatory regime established by the Act. Although a federal court may disagree with the regulatory approach taken by the agency with responsibility for issuing permits under the Act, such disagreement alone is no basis for the creation of federal common law.16

Respondents strenuously argue that federal common law continues to be available, stressing that neither in the permits nor the enforcement order are there any effluent limitations on overflows. This argument, we think, is something of a red herring. The difference in treatment between overflows and treated effluent by the agencies is due to differences in the nature of the problems, not the extent to which the problems have been addressed.17 The relevant question with overflow discharges is not, as with discharges of treated sewage, what concentration of various pollutants will be permitted. Rather the question is what degree of control will be required in *324preventing overflows and ensuring that the sewage undergoes treatment. This question is answered by construction plans designed to accommodate a certain amount of sewage that would otherwise be discharged on overflow occasions. The EPA has not promulgated regulations mandating specific control guidelines because of a recognition that the problem is “site specific.” See, e. g., EPA Program Requirements Memorandum PRM No. 75-34 (Dec. 16, 1975):

“The costs and benefits of control of various portions of pollution due to combined sewer overflows and bypasses vary greatly with the characteristics of the sewer and treatment system, the duration, intensity, frequency, and aerial extent of precipitation, the type and extent of development in the service area, and the characteristics, uses and water quality standards of the receiving waters. Decisions on grants for control of combined sewer overflows, therefore, must be made on a case-by-case basis after detailed planning at the local level.”

See also EPA, Report to Congress on Control of Combined Sewer Overflow in the United States 7-1, 7-13 (MCD-50, 1978). Decision is made on a case-by-case basis, through the permit procedure, as was. done here. Demanding specific regulations of general applicability before concluding that Congress has addressed the problem to the exclusion of federal common law asks the wrong question. The question is whether the field has been occupied, not whether it has been occupied in a particular manner.18

*325The invocation of federal common law by the District Court and the Court of Appeals in the face of congressional legislation supplanting it is peculiarly inappropriate in areas as complex as water pollution control. As the District Court noted:

“It is well known to all of us that the arcane subject matter of some of the expert testimony in this case was sometimes over the heads of all of us to one height or another. I would certainly be less than candid if I did not acknowledge that my grasp of some of the testimony was less complete than I would like it to be . . . .” App. to Pet. for Cert. P-4.

Not only are the technical problems difficult — doubtless the reason Congress vested authority to administer the Act in administrative agencies possessing the necessary expertise— but the general area is particularly unsuited to the approach inevitable under a regime of federal common law. Congress criticized past approaches to water pollution control as being “sporadic” and “ad hoc,” S. Rep. No. 92-414, p. 95 (1971), 2 Leg. Hist. 1511, apt characterizations of any judicial approach applying federal common law, see Wilburn Boat Co. v. Fireman’s Fund Ins. Co., 348 U. S. 310, 319 (1955).

It is also significant that Congress addressed in the 1972 Amendments one of the major concerns underlying the recognition of federal common law in Illinois v. Milwaukee. We were concerned in that ease that Illinois did not have any forum in which to protect its interests unless federal common law were created. See 406 U. S., at 104, 107. In the 1972 *326Amendments Congress provided ample opportunity for a State affected by decisions of a neighboring State’s permit-granting agency to seek redress. Under §402 (b)(3), 33 U. S. C. § 1342 (b)(3), a state permit-granting agency must ensure that any State whose waters may be affected by the issuance of a permit receives notice of the permit application and the opportunity to participate in a public hearing. Wisconsin law accordingly guarantees such notice and hearing, see Wis. Stat. Ann. §§ 147.11, 147.13 (West Supp. 1980-1981). Respondents received notice of each of the permits involved here, and public hearings were held, but they did not participate in them in any way. Section 402 (b) (5), 33 U. S. C. § 1342 (b) (5), provides that state permit-granting agencies must ensure that affected States have an opportunity to submit written recommendations concerning the permit applications to the issuing State and the EPA, and both the affected State and the EPA must receive notice and a statement of reasons if any part of the recommendations of the affected State are not accepted. Again respondents did not avail themselves of this statutory opportunity. Under § 402 (d) (2) (A), 33 U. S. C. § 1342 (d)(2)(A) (1976 ed., Supp. Ill), the EPA may veto any permit issued by a State when waters of another State may be affected. Respondents did not request such action. Under § 402 (d) (4) of the Act, 33 U. S. C. § 1342 (d) (4) (1976 ed., Supp. Ill), added in .1977, the EPA itself may issue permits if a stalemate between an issuing and objecting State develops. The basic grievance of respondents is that the permits issued to petitioners pursuant to the Act do not impose stringent enough controls on petitioners’ discharges. The statutory scheme established by Congress provides a forum for the pursuit of such claims before expert agencies by means of the permit-granting process. It would be quite inconsistent with this scheme if federal courts were in effect to “write their own ticket” under the guise of federal common law after permits have already been issued and permittees have been planning and operating in reliance on them.

*327Respondents argue that congressional intent to preserve the federal common-law remedy recognized in Illinois v. Milwaukee is evident in §§ 510 and 505 (e) of the statute, 33 U. S. C. §§ 1370, 1365 (e).19 Section 510 provides that nothing in the Act shall preclude States from adopting and enforcing limitations on the discharge of pollutants more stringent than those adopted under the Act.20 It is one thing, how*328ever, to say that States may adopt more stringent limitations through state administrative processes, or even that States may establish such limitations through state nuisance law, and apply them to in-state dischargers. It is quite another to say that the States may call upon federal courts to employ federal common law to establish more stringent standards applicable to out-of-state dischargers. Any standards established under federal common law are federal standards, and so the authority of States to impose more stringent standards under § 510 would not seem relevant. Section 510 clearly contemplates state authority to establish more stringent pollution limitations; nothing in it, however, suggests that this was to be done by federal-court actions premised on federal common law.

Subsection 505 (e) provides:

“Nothing in this section shall restrict any right which any person (or class of persons) may have under any statute or common law to seek enforcement of any effluent standard or limitation or to seek any other relief (including relief against the Administrator or a State agency)” (emphasis supplied).

Respondents argue that this evinces an intent to preserve the federal common law of nuisance. We, however, are inclined to view the quoted provision as meaning what it says: that nothing in § 505, the citizen-suit provision, should be read as limiting any other remedies which might exist.

Subsection 505 (e) is virtually identical to subsections in the citizen-suit provisions of several environmental statutes.21 *329The subsection is common language accompanying citizen-suit provisions and we think that it means only that the provision of such suit does not revoke other remedies. It most assuredly cannot be read to mean that the Act as a whole does not supplant formerly available federal common-law actions but only that the particular section authorizing citizen suits does not do so. No one, however, maintains that the citizen-suit provision pre-empts federal common law.

We are thus not persuaded that § 505 (e) aids respondents in this case, even indulging the unlikely assumption that the reference to “common law” in § 505 (e) includes the limited federal common law as opposed to the more routine state common law. See Committee for Consideration of Jones Falls Sewage System v. Train, 539 F. 2d, at 1009, n. 9.22

The dissent considers “particularly revealing,” post, at 343, a colloquy involving Senators Griffin, Muskie, and Hart, concerning the pendency of an action by the EPA against Reserve Mining Co. Senator Griffin expressed concern that “one provision in the conference agreement might adversely *330affect a number of pending lawsuits brought under the Refuse Act of 1899,” including the Reserve Mining litigation. 1 Leg. Hist. 190. The provision which concerned Senator Griffin, enacted as § 402 (k), 86 Stat. 883, 33 U. S. C. § 1342 (k), provides, in pertinent part:

“Until December 31, 1974, in any case where a permit for discharge has been applied for pursuant to this section, but final administrative disposition of such application has not been made, such discharge shall not be a violation of (1) section 301, 306, or 402 of this Act, or (2) section 13 of the Act of March 3, 1899, unless the Administrator or other plaintiff proves that final administrative disposition of such application has not been made because of the failure of the applicant to furnish information reasonably required or requested in order to process the application.”

Senator Griffin was concerned about the relation between this provision and § 4 (a) of the bill, which provided that “[n]o suit, action or other proceeding lawfully commenced by or against the Administrator or any other officer or employee of the United States in his official capacity or in relation to the discharge of his official duties under the Federal Water Pollution Control Act as in effect immediately prior to the date of enactment of the Act shall abate by reason of the taking effect of the amendment made by section 2 of this Act.” Senator Griffin stated that “when these provisions are read together, it is not altogether clear what effect is intended with respect to pending Federal court suits against polluters violating the Refuse Act of 1899.”

Senator Muskie responded to Senator Griffin’s concerns by quoting § 4 («•) and stating that “[w]ithout any question it was the intent of the conferees that this provision include enforcement actions brought under the Refuse Act, the Federal Water Pollution Control Act, and any other acts of Congress.” 1 Leg. Hist. 193. Later Senator Hart stated: “It is *331my understanding, . . . after the explanation of the Senator from Maine, that the suit now pending against the Reserve Mining Co., under the Refuse Act of 1899 will in no way be affected nor will any of the other counts under the existing Federal Water Pollution Control Act or other law.” Id., at 211.23 When Senator Muskie’s and Hart’s remarks are viewed in this context it is clear that they do not bear on the issue now before the Court. In the first place, although there was a federal common-law claim in the Reserve Mining litigation, Senator Griffin focused on the Refuse Act of 1899— not federal common law. Senator Muskie, with his reference to “other acts of Congress,” rather clearly was not discussing federal common law. Most importantly, however, Senator Muskie based his response to Senator Griffin — that the Re^ serve Mining suit would not be affected — on a specific section of the bill, § 4 (a), which is not applicable to suits other than those brought by or against the Federal Government and pending when the Amendments were enacted. Senator Hart based his response on the explanation given by Senator Muskie. Even if we assumed that the legislators were focusing on the federal common-law aspects of the Reserve Mining litigation (and we do not think they were), Senators Muskie and Hart informed Senator Griffin that the Reserve Mining suit was not affected because of § 4 (a), and not at all because the Act did not displace the federal common law of nuisance. Senator Griffin’s question focused on § 4 (a); understandably, so did the assurances he received. Nothing *332about the colloquy suggests any intent concerning the continued validity of federal common law. The issue simply did not come up because Senator Griffin’s concerns were fully answered by a particular section not applicable in the case before us.24

We therefore conclude that no federal common-law remedy was available to respondents in this case. The judgment of the Court of Appeals is therefore vacated, and the case is remanded for proceedings consistent with this opinion.

It is so ordered.

with whom Justice Marshall and Justice Stevens join, dissenting.

Nine years ago, in Illinois v. Milwaukee, 406 U. S. 91 (1972), this Court unanimously determined that Illinois could bring a federal common-law action against the city of *333Milwaukee, three other Wisconsin cities, and two sewerage commissions. At that time, Illinois alleged that the discharge of raw and untreated sewage by these Wisconsin entities into Lake Michigan created a public nuisance for the citizens of Illinois. The Court remitted the parties to an appropriate federal district court, “whose powers are adequate to resolve the issues.” Id., at 108.

Illinois promptly initiated the present litigation,1 and pursued it through more than three years of pretrial discovery, a 6-month trial that entailed hundreds of exhibits and scores of witnesses, extensive factual findings by the District Court, App. F to Pet. for Cert., and an exhaustive review of the evidence by the Court of Appeals. 599 F. 2d 151, 167-177 (CA7 1979). Today, the Court decides that this 9-year judicial exercise has been just a meaningless charade, cf. Hughes Tool Co. v. Trans World Airlines, Inc., 409 U. S. 363, 389, 390 (1973) (dissenting opinion), inasmuch as, it says, the federal common-law remedy approved in Illinois v. Milwaukee was implicitly extinguished by Congress just six months after the 1972 decision. Because I believe that Congress intended no such extinction, and surely did not contemplate the result reached by the Court today, I respectfully dissent.

I

The Courtis analysis of federal common-law displacement rests, I am convinced, on a faulty assumption. In contrasting congressional displacement of the common law with federal pre-emption of state law,2 the Court assumes that as *334soon as Congress “addresses a question previously governed” by federal common law, “the need for such an unusual exercise of lawmaking by federal courts disappears.” Ante, at 314. This “automatic displacement” approach is inadequate in two respects. It fails to reflect the unique role federal common law plays in resolving disputes between one State and the citizens or government of another. In addition, it ignores this Court’s frequent recognition that federal common law may complement congressional action in the fulfillment of federal policies.

It is well settled that a body of federal common law has survived the decision in Erie R. Co. v. Tompkins, 304 U. S. 64 (1938). Erie made clear that federal courts, as courts of limited jurisdiction, lack general power to formulate and impose their own rules of decision. Id., at 78. The Court, however, did not there upset, nor has it since disturbed, a deeply rooted, more specialized federal common law that has arisen to effectuate federal interests embodied either in the Constitution or an Act of Congress.3 Chief among the fed*335eral interests served by this common law are the resolution of interstate disputes and the implementation of national statutory or regulatory policies.

Both before and after Erie, the Court has fashioned federal law where the interstate nature of a controversy renders inappropriate the law of either State. See, e. g., Nebraska v. Wyoming, 325 U. S. 589 (1945); Hinderlider v. La Plata Co., 304 U. S. 92, 110 (1938); Kansas v. Colorado, 206 U. S. 46, 95, 97-98 (1907) (apportioning waters of interstate stream). See also Cissna v. Tennessee, 246 U. S. 289, 296 (1918); Howard v. Ingersoll, 13 How. 381 (1852) (resolving interstate boundary conflict). When such disputes arise, it is clear under our federal system that laws of one State cannot impose upon the sovereign rights and interests of another. The Constitution, by Art. III, § 2, explicitly extends the judicial power of the United States to controversies between a State and another State or its citizens, and this Court, in equitably resolving such disputes, has developed a body of “what may not improperly be called interstate common law.” Kansas v. Colorado, 206 U. S., at 98.

Long before the 1972 decision in Illinois v. Milwaukee, federal common law enunicated by this Court assured each State the right to be free from unreasonable interference with its natural environment and resources when the interference stems from another State or its citizens. Georgia v. Tennessee Copper Co., 206 U. S. 230, 237-239 (1907); Missouri v. Illinois, 200 U. S. 496, 520, 526 (1906). See New Jersey v. City of New York, 283 U. S. 473 (1931); New York v. New Jersey, 256 U. S. 296 (1921). The right to such federal protection is a consequence of each State's entry into the Union and its commitment to the Constitution. In the words of Justice Holmes, speaking for the Court:

“When the States by their union made the forcible *336abatement of outside nuisances impossible to each, they did not thereby agree to submit to whatever might be done. They did not renounce the possibility of making reasonable demands on the ground of their still remaining gwcm-sovereign interests; and the alternative to force is a suit in this court.” Georgia v. Tennessee Copper Co., 206 U. S., at 237.

This Court also has applied federal common law where federally created substantive rights and obligations are at stake. Thus, the Court has been called upon to pronounce common law that will fill the interstices of a pervasively federal framework, or avoid subjecting relevant federal interests to the inconsistencies in the laws of several States. Textile Workers v. Lincoln Mills, 353 U. S. 448, 456-457 (1957); United States v. Standard Oil Co., 332 U. S. 301, 305 (1947); Clearfield Trust Co. v. United States, 318 U. S. 363, 366-367 (1943); D’Oench, Duhme & Co. v. Federal Deposit Ins. Corp., 315 U. S. 447 (1942). If the federal interest is sufficiently strong, federal common law may be drawn upon in settling disputes even though the statute or Constitution alone provides no precise answer to the question posed. See, e. g., Textile Workers v. Lincoln Mills, 353 U. S., at 458; Clearfield Trust Co. v. United States, 318 U. S., at 368-370. See generally United States v. Little Lake Misere Land Co., 412 U. S. 580, 593 (1973) (“the inevitable incompleteness presented by all legislation means that interstitial federal lawmaking is a basic responsibility of the federal courts”).

Each of these sources of federal common law was recognized in Illinois v. Milwaukee. The Court there concluded that the common law of interstate nuisance supplied the requisite federal-question jurisdiction to bring an action in District Court. In so deciding, the Court reasoned that it was appropriate for federal courts to fashion federal common law “where there is an overriding federal interest in the need for a uniform rule of decision or where the controversy *337touches basic interests of federalism.” 406 U. S., at 105, n. 6. The Court relied heavily upon interstate air pollution and water allocation cases where the complaining party was a State invoking the Court’s original jurisdiction. Id., at 1CMH06. In addition, it recounted the history of federal interstate water quality legislation and suggested that the abiding federal interest in the purity of interstate waters justified application of federal common law. Id., at 101-103. Significantly, the Court found no barrier to federal common law despite the number of federal statutes and regulations that already provided remedies to abate pollution in interstate waters. Id., at 103.

Thus, quite contrary to the statements and intimations of the Court today, ante, at 323, 325, 327, n. 19, Illinois v. Milwaukee did not create the federal common law of nuisance. Well before this Court and Congress acted in 1972, there was ample recognition of and foundation for a federal common law of nuisance applicable to Illinois’ situation.4 Congress cannot be presumed to have been unaware of the relevant common-law history, any more than it can be deemed to have been oblivious to the decision in Illinois v. *338Milwaukee, announced six months prior to the passage of the Federal Water Pollution Control Act Amendments of 1972 (Act or Amendments), 86 Stat. 816. The central question is whether, given its presumed awareness, Congress, in passing these Amendments, intended to prevent recourse to the federal common law of nuisance.

The answer to this question, it seems to me, requires a more thorough exploration of congressional intent than is offered by the Court. Congress had “spoken to” the particular problem of interstate water pollution as far back as 1888,5 and in 1948 did so in a broad and systematic fashion with the enactment of the Water Pollution Control Act (also known as the Clean Water Act).6 In Illinois v. Milwaukee, the Court properly regarded such expressions of congressional intent as not an obstacle but an incentive to application of the federal common law. 406 U. S., at 102-103. The fact that Congress in 1972 once again addressed the complicated and difficult problem of purifying our Nation’s waters should not be taken as presumptive evidence, let alone conclusive proof, that Congress meant to foreclose pre-existing approaches to controlling interstate water pollution.7 Where the possi*339ble extinction of federal common law is at issue, a reviewing court is obligated to look not only to the magnitude of the legislative action but also with some care to the evidence of specific congressional intent.8

II

In my view, the language and structure of the Clean Water Act leave no doubt that Congress intended to preserve the federal common law of nuisance. Section 505 (e) of the Act reads:

“Nothing in this section shall restrict any right which any person (or class of persons) may have under any statute or common law to seek enforcement of any effluent standard or limitation or to seek any other relief (including relief against the Administrator or a State agency).” 33 U. S. C. § 1365 (e) (emphasis added).

The Act specifically defines “person” to include States, and thus embraces respondents Illinois and Michigan. § 502 (5), *34033 U. S. C. § 1362 (5). It preserves their right to bring an action against the governmental entities who are charged with enforcing the statute. Most important, as succinctly-stated by the Court of Appeals in this case: “There is nothing in the phrase 'any statute or common law’ that suggests that this provision is limited to state common law.” 599 F. 2d, at 163. To the best of my knowledge, every federal court that has considered the issue has concluded that, in enacting § 505 (e), Congress meant to preserve federal as well as state common law.9

Other sections of the Clean Water Act also support the conclusion that Congress in 1972 had no intention of extinguishing the federal common law of nuisance. Although the Act established a detailed and comprehensive regulatory system aimed at eliminating the discharge of pollutants into all navigable waters, it did not purport to impose a unitary enforcement structure for abating water pollution. In par*341ticular, Congress expressly provided that the effluent limitations promulgated under the Act do not preclude any State from establishing more stringent limitations. § 510, 33 U. S. C. § 1370. It also made clear that federal officers or agencies are not foreclosed from adopting or enforcing stricter pollution controls and standards than those required by the Act. § 511 (a), 33 U. S. C. § 1371 (a).

Thus, under the statutory scheme, any permit issued by the EPA or a qualifying state agency does not insulate a dis-charger from liability under other federal or state law.10 To the contrary, the permit granted pursuant to § 402 (k), 33 U. S. C. § 1342 (k), confers assurances with respect to certain specified sections of the Act, but the requirements under other provisions as well as separate legal obligations remain unaffected. See EPA v. State Water Resources Control Board, 426 U. S. 200, 205 (1976). Congress plainly anticipated that dischargers might be required to meet standards more stringent than the minimum effluent levels approved by the EPA. Those more stringent standards would necessarily be established by other statutes or by common law. Because the Act contemplates a shared authority between the Federal Government and the individual States, see, e. g., § 101 (b), 33 U. S. C. § 1251 (b) (1976 ed., Supp. Ill), it is entirely understandable that Congress thought it neither imperative nor desirable to insist upon an exclusive approach to the improvement of water quality.11

The Court offers three responses to this view of congressional intent. With regard to the language of § 505 (e), it attributes critical significance to the words “this section,” *342and concludes that Congress meant only to assure that the citizen-suit provision did not extinguish formerly available federal common-law actions. Ante, at 328-330. The Court thus reads § 505 (e) as though Congress had said that “ This section’ does not take away any pre-existing remedies, but the remainder of the statute does.” This is an extremely strained reading of the statutory language,12 and one that is at odds with the manifest intent of Congress to permit more stringent remedies under both federal and state law. See §§ 510, 511, 33 U. S. C. §§ 1370, 1371. If § 505 (e) is to be construed as the Court suggests, then it authorizes the abrogation of all pre-existing rights, both statutory and common law, in the area of water pollution control. The Court’s construction therefore, would render suspect, if not meaningless, the Act’s other provisions. Rather than interpreting § 505 (e) as a license to supplant all legal remedies outside the Act itself, I would construe the reference to “this section” as simply preventing pre-existing rights of action from being subjected to the procedural and jurisdictional limitations imposed by § 505 on persons who would sue under the Act.

The Court also relies on certain language contained in the legislative history of the 1972 Amendments. Ante, at 317-319. Based on the remarks of several of the Act’s proponents that this was the most comprehensive water pollution bill prepared to date, the Court finds a strong congressional suggestion that there is no room for improvement through the federal common law. But there is nothing talismanic about such generalized references. The fact that legislators may characterize their efforts as more “comprehensive” than prior legislation hardly prevents them from authorizing the continued existence of supplemental legal and equitable solutions to the broad and serious problem addressed.13 More*343over, the Court ignores express statements of legislative intent that contradict its position. The Senate Report accompanying the 1972 legislation explicitly describes the congressional intent informing § 505 (e):

“It should be noted, however, that the section would specifically preserve any rights or remedies under any other law. Thus, if damages could be shown, other remedies would remain available. Compliance with requirements under this Act would not be a defense to a common law action for pollution damages.” S. Rep. No. 92-414, p. 81 (1971), reprinted in 2 Legislative History of the Water Pollution Control Act Amendments of 1972 (Committee Print compiled for the Senate Committee on Public Works by the Library of Congress), Ser. No. 93-1, p. 1499 (1973) (Leg. Hist.).14

This deliberate preservation of all remedies previously available at common law makes no distinction between the common law of individual States and federal common law. Indeed, the legislative debates indicate that Congress was specifically aware of the presence of federal common law, and intended that it would survive passage of the 1972 Amendments. In one particularly revealing colloquy on the Senate floor, Senator Griffin noted the pendency of a suit challenging the dumping of iron ore pollutants into Lake *344Superior. 1 Leg. Hist. 191. See Reserve Mining Co. v. EPA, 514 F. 2d 492 (CA8 1975) (en banc). The Senator inquired whether the suit, which was based in part on the federal common law of nuisance,15 would be affected by passage of the 1972 Amendments. Senators Muskie16 and Hart each responded that the new legislation would not affect or hinder “the suit now pending against the Reserve Mining Co., under the Refuse Act of 1899 ...[,] the existing Federal Water Pollution Control Act or other law.” 1 Leg. Hist. 211 (Sen. Hart) (emphasis added).17

*345Finally, the Court attaches significance to the fact that the 1972 Amendments provided a more rigorous administrative mechanism for addressing interstate controversies. Ante, at 325-326. The Court evidently regards the provision of a new administrative abatement process as a type of jurisdictional requirement, for it criticizes Illinois’ failure to invoke the mechanism before seeking any form of judicial relief. Ante, at 326. Even if this were the case, the new notice and hearing procedure became available only two years after Illinois commenced this action. There is no suggestion that Illinois failed to pursue administrative abatement under the then-applicable federal statute. Indeed, it is undisputed that Illinois made prolonged and diligent efforts to secure administrative relief.18 Nonetheless, the Court in effect concludes that it is not enough to exhaust administrative remedies that existed at the time a common-law action was initiated; a complainant must also be prepared to pursue new and wholly unforeseen administrative avenues even as it seeks a final judgment in federal court. I am aware of no ease that adopts so harsh an approach to the pursuit of administrative remedies, and I see no basis for imposing such a requirement in this context.

Moreover, contrary to what the Court implies, Congress never intended that failure to participate in the § 402 administrative process would serve as a jurisdictional bar. Nothing in the language of § 402 suggests that a neighboring State’s participation in the permit-granting process is anything other than voluntary and optional.19 Indeed, the Con-*346ferenee Committee considering the 1977 amendments to the Act was presented with a proposal that would have made such participation a jurisdictional prerequisite.20 This proposal was not adopted by the Conference Committee, and among its opponents was the Department of Justice. In a letter sent to all conferees, the Department made clear its understanding that, absent such an amendment, the federal common law would continue to be relied upon in the national effort to control water pollution.21

*347The Justice Department’s position on the survival of federal common law is consistent with the stance taken by the EPA both in this litigation and throughout the period since the 1972 Amendments were enacted. The EPA in fact has relied upon the federal common law of nuisance in addition to the remedies available under the statute in seeking to protect water quality.22 As the agency charged with enforcing and implementing the Act, EPA’s interpretation of the scope and limits of that statute is entitled to considerable deference. See Udall v. Tallman, 380 U. S. 1, 16 (1965). Where, as here, the agency has publicly and consistently acted upon its interpretation, congressional silence is not without significance, particularly since this area has been a subject of frequent and intense legislative attention. And where, as here, the agency’s continued reliance on federal common law is firmly grounded in the language and structure of the statute, I fail to see how the Court can so lightly disregard its interpretation.

*348Ill

Assuming that Congress did preserve a federal common law of nuisance, and that respondents properly stated federal common-law claims for relief, there remains the question whether the particular common law applied here was reasonable. Because of its ruling, the Court does not explicitly address this question. Nonetheless, in its detailed review of respondents’ claims, the Court in effect concludes that the federal common law applied by the District Court and the Court of Appeals was defective. In particular, the Court asserts that federal courts may not exceed the statutory minimum approach sanctioned by Congress, see ante, at 323, and may not use federal power to impose a State’s more stringent pollution limitation standards upon out-of-state polluters. See ante, at 327-328. In contrast, I believe the courts below acted correctly in both respects.

As the Court of Appeals properly recognized, 599 F. 2d, at 164, the determination by Congress to preserve rights of action at federal common law did not grant federal courts the freedom to disregard the statutory and regulatory structure approved by Congress. We noted in Illinois v. Milwaukee that “the various federal environmental protection statutes will not necessarily mark the outer bounds of the federal common law, [but] they may provide useful guidelines in fashioning such rules of decision.” 406 U. S., at 103, n. 5. These guidelines, however, bear primarily on the problems of proof faced by the parties; they do not determine the exclusive source of the law to be applied.

In this instance, problems of proof arise under a familiar form of common-law action. A public nuisance involves unreasonable interference with a right common to the general public.23 Drawing on the Court’s decision in Georgia v. Ten*349nessee Copper Co., 206 U. S., at 238-239, the Court of Appeals concluded that nuisance is established at federal common law only if “the defendant is carrying on an activity that is causing an injury or significant threat of injury to some cognizable interest of the complainant.” 599 F. 2d, at 165. Whether a particular interference qualifies as unreasonable, whether the injury is sufficiently substantial to warrant injunctive relief, and what form that relief should take are questions to be decided on the basis of particular facts and circumstances.24 The judgments at times are difficult, but they do not require courts to perform functions beyond their traditional capacities or experience.25

When choosing the precise legal principles to apply, common-law courts draw upon relevant standards of conduct available in their communities. Where federal common law is concerned, “th[is] choice-of-law task is a federal task for federal courts.” United States v. Little Lake Misere Land Co., 412 U. S., at 592. At the same time, while federal law *350controls a particular question or problem, state law may furnish an appropriate measure of the content of this federal law. See, e. g., Board of Comm’rs v. United States, 308 U. S. 343, 349-352 (1939). See also Textile Workers v. Lincoln Mills, 353 U. S., at 457; Clearfield Trust Co. v. United States, 318 U. S., at 367. What the Court today characterizes as the inappropriate application of more stringent standards from Illinois state law in fact reflects a federal common-law court’s proper exercise of choice-of-law discretion.26

The Act sets forth certain effluent limitations. As did the Court of Appeals,27 a court applying federal common law in a given instance may well decline to impose effluent limitations more stringent than those required by Congress, because the complainant has failed to show that stricter standards will abate the nuisance or appreciably diminish the threat of injury. But it is a far different proposition to pronounce, as does the Court today, that federal courts “lack authority to impose more stringent effluent limitations under federal common law than those imposed” under the statutory scheme. Ante, at 320 (emphasis added). The authority of the federal courts in this area was firmly established by the decision in Illinois v. Milwaukee. In delineating the legitimate scope of the federal common law, the Court there expressly noted the relevance of state standards, adding that “a State with high water-quality standards may well ask that its strict standards be honored and that it not be compelled to lower itself to the more degrading standards of a neighbor.” (Emphasis added.) 406 U. S., at 107. The Act attributes comparable respect to the stricter effluent limita*351tion levels imposed by individual States. § 510, 33 U. S. C. § 1370. Since both the Court and Congress fully expected that neighboring States might differ in their approaches to the regulation of the discharge of pollutants into their navigable waters, it is odd, to say the least, that federal courts should now be deprived of the common-law power to effect a reconciliation of these differences.

The problem of controlling overflows is particularly amenable to application of this common-law authority. As the courts below found, see 599 F. 2d, at 167-168, the sewer systems operated by petitioners include some 239 bypass or overflow points from which raw sewage is. discharged directly into Lake Michigan or into rivers that flow into the lake. In a single month in 1976, discharge from 11 of the 239 discrete overflow points amounted to some 646 million gallons of untreated sewage. Ibid. The trial court determined that these untreated fecal wastes, containing billions of pathogenic bacteria and viruses, are periodically transported by prevailing currents into the Illinois waters of Lake Michigan. The court further found that the presence of these pathogens in Illinois waters poses a significant risk of injury to Illinois residents, threatening to contaminate drinking water supplies and infect swimmers.28

Pursuant to the Act, publicly owned treatment works then in existence must apply “secondary treatment as defined by the Administrator” as of July 1, 1977. §§ 301 (b)(1)(B), 304(d)(1), 33 U. S. C. §§1311 (b)(1)(B), 1314(d)(1).29 *352No provision of the Act explicitly addresses the discharge of raw sewage into public waters from overflow points. Indeed, Congress in 1977 expressed concern that combined sewer overflows were a significant source of untreated sewage polluting the Nation’s waters, and it commissioned a study of the problem with a view toward possible further legislation.30 While the Administrator has issued regulations that define secondary treatment in terms of certain minimum levels of effluent quality, he also has acknowledged that combined sewer overflows raise special concerns that must be resolved on a case-by-case basis.31 This record demonstrates that both Congress and the Administrator recognized the inadequacy of the statutory scheme. It surely does not show that these responsible parties intended no role for the federal common law.

The lower courts in this case carefully evaluated the regulatory systems developed by each State to deal with the overflow problem. It was determined that the standards promulgated under the Illinois regulatory scheme were more stringent than those developed by the Wisconsin agency or imposed on petitioners under the Wisconsin state-court judgment. See 599 F. 2d, at 171-173. The District Court’s order imposed standards that reflected the more rigorous approach adopted in Illinois to restore and protect Illinois *353waters.32 The Court of Appeals noted that Wisconsin had allowed petitioners more time in which to eliminate or “correct” the overflow problem, but that petitioners conceded the feasibility of complying with the District Court’s deadlines. Id., at 172, 177. In my view, the Court of Appeals acted responsibly and in a manner wholly consistent with the common-law jurisdiction envisioned by the Court in Illinois v. Milwaukee.

IV

There is one final disturbing aspect to the Court’s decision. By eliminating the federal common law of nuisance in this area, the Court in effect is encouraging recourse to state law wherever the federal statutory scheme is perceived to offer inadequate protection against pollution from outside the State, either in its enforcement standards or in the remedies afforded. This recourse is now inevitable under a statutory scheme that accords a significant role to state as well as federal law. But in the present context it is also unfortunate, since it undermines the Court’s prior conclusion that it is federal rather than state law that should govern the regulation of interstate water pollution. Illinois v. Milwaukee, 406 U. S., at 102. Instead of promoting a more uniform federal approach to the problem of alleviating interstate pollution, I fear that today’s decision will lead States to turn to their *354own courts for statutory or common-law assistance in filling the interstices of the federal statute. Rather than encourage such a prospect, I would adhere to the principles clearly enunciated in Illinois v. Milwaukee, and affirm the judgment of the Court of Appeals.