OPINION

GME Consultants, Inc. and CCST, Inc. challenge the exemption of Independent School District No. 200 from Minnesota’s mechanics’ lien statute, Minn.Stat. § 514.01 (1992). We affirm.

FACTS

Respondent Independent School District No. 200 owned a parcel of undeveloped real property in Hastings, Minnesota. It leased the property to a farmer. On April 17,1991, the school district entered into a contingent purchase agreement for the sale of approximately 20 acres of that property to a commercial developer, respondent Oak Grove Enterprises, Inc. (Oak Grove). The written purchase agreement contained only an approximate property description subject to the Board of Education’s determination of its specific land needs for school purposes.

The agreement contained contingencies regarding engineering tests to be obtained and paid for by Oak Grove. Oak Grove hired appellants GME Consultants and CCST, Inc., two engineering firms, to perform the engineering services. 1 Appellants performed, but Oak Grove defaulted on the agreement with the school district and failed to pay appellants for their services. Appellants filed mechanics’ hens against the school district’s property and eventually filed this action to enforce the hens. The district court granted summary judgment for the school district, applying the common law pubhc property exemption to Minnesota’s mechanics’ hen law.

ISSUE

Is the school district’s property exempt from Minnesota’s mechanics’ hen statute, Minn.Stat. § 514.01 (1992)?

ANALYSIS

On this appeal from summary judgment, the parties do not dispute the material facts. Appellants contend that the district court incorrectly apphed the pubhc property exemption to the land in question. Therefore, we must determine whether the district court correctly apphed the law. See Hubred v. Control Data Corp., 442 N.W.2d 308, 310 (Minn. 1989). In so doing, we are not bound by and need not give deference to the district court’s determination of the purely legal question. See Frost-Benco Elec. Ass’n v. Minnesota Pub. Utils. Comm’n, 358 N.W.2d 639, 642 (Minn. 1984).

Minnesota’s mechanics’ hen statute does not contain a statutory exemption for a school district’s property. See Minn.Stat. § 514.01 (1992). A common law pubhc property exemption, however, was well-established as early as 1888. In that year, the Minnesota Supreme Court first addressed the issue in Jordan v. Board of Educ. of Taylor’s Falls, 39 Minn. 298, 39 N.W. 801 (1888). The court apphed the then nearly universal rule that pubhc property held for and devoted to a pubhc Use is exempt from mechanics’ hen laws. Id. at 299, 39 N.W. at 802. See generally 10 Eugene McQuillan, *76 The Law of Municipal Corporations, § 28.58 at 238 (3d ed. 1990). The Jordan court held that a public schoolhouse was not subject to a lien under a predecessor mechanics’ hen statute. Id.

The issue arose again in two later cases. In Burlington Mfg. Co. v. Board of Courthouse & City Hall Comm’rs, 67 Minn. 327,69 N.W. 1091 (1897), the court held that a subcontractor who furnished materials for building a new courthouse and city hall could not enforce a mechanics’ hen on the property. Six years later, the court apphed the same rule to invalidate a hen filed against logs owned by the United States government in Rowley v. Conklin, 89 Minn. 172, 175, 94 N.W. 548, 549 (1903).

With this backdrop of Minnesota precedent, appellants urge this court “to bring the mechanics’ hen laws of the State of Minnesota into the 21st Century” and to enforce their hens against the school district. It is this court’s responsibility to decide this case in a manner consistent with existing law. State v. Hannuksela, 452 N.W.2d 668, 673 n. 7 (Minn. 1990). Although stare decisis is not an inflexible rule of law, departure from precedent is rare, especially in the field of property law “where rights may have become vested in rehance upon the decisions of this court.” Johnson v. Chicago, Burlington & Quincy RR, 243 Minn. 58, 68, 66 N.W.2d 763, 770 (1954). On the other hand, where societal conditions or other reasons for a common law rule cease to exist, blind obedience to the past is not required. Id. at 69, 66 N.W.2d at 771.

Minnesota case law exempting pubhe property from mechanics’ hens, albeit dated, however, remains solidly rooted in pubhe policy. First, pubhe property is owned by municipal corporations, school districts, and other quasi-municipal corporations which are expressly created to administer the local affairs of the state government. See Jordan, 39 Minn, at 299, 39 N.W. at 801. They are pubhe entities created for pubhe purposes. School districts in particular “are arms of the state and are given corporate powers solely for the exercise of pubhe functions for educational purposes.” Village of Blaine v. Independent Sch. Dist. No. 12, Anoka County, 272 Minn. 343, 351, 138 N.W.2d 32, 38 (1965). The school board has the broad “general charge of the business of the district, the school houses, and of the interests of the schools thereof.” Minn.Stat. § 123.35, subd. 1 (1992). The pohey exempting pubhe property from mechanics’ hens is therefore aimed at protecting ah who benefit from the services local government provides, i.e., the general pubhe.

Appellants argue that the school district’s undeveloped land lost its pubhe character when it was leased to a farmer for profit or, alternatively, when the purchase agreement to sell it to Oak Grove was executed. The school district originally purchased the property for school purposes. In our view, the execution of neither the farm lease nor the purchase agreement to Oak Grove marks a break from the school district’s original intention. First, the rental was a reasonable use of the land and was not inconsistent with the objective of retaining the property for school purposes. Second, at the time it entered into the purchase agreement, the school district had not finally determined its school needs. In fact, it expressly reserved the right to change the legal description of the property sold pending this determination. Nor does the purchase agreement indicate any intention that the school district planned any non-public use of the property.

Moreover, subjecting the undeveloped property to mechanics’ hens either during the farm lease or pending the contingent sale would defeat the pubhe pohey behind the exemption. 2 A school district needs undevel *77 oped land to plan and provide for its future needs. Subjecting such lands to mechanics’ liens while the school district plans the construction of a new school or while it arranges the sale of extraneous land, would penalize a school board for planning. It would strip the school board of needed flexibility. Construing such legitimate public activity as a nonpublic use would not serve the public good. Cf. R.E. Short Co. v. City of Minneapolis, 269 N.W.2d 331, 337 (Minn. 1978) (in determining whether particular expenditure serves public purpose, “ ‘public purpose’ should be broadly construed to comport with the changing conditions of modern life”).

DECISION

Undeveloped land purchased for future school district needs is exempt from Minnesota’s mechanics’ lien law. Leasing such land to a farmer pending a final decision on school needs was a legitimate use and did not change its public character. Similarly, a contingent sale of a portion of such land did not change the use of the land to a non-public use. Therefore, the district court correctly applied the public property exemption to the school district’s land.

Affirmed.