delivered the opinion of the Court:

A multitude of immaterial questions were raised by the pleadings in the court below, and a complication arose over certain proceedings had after notice of appeal and designation of the record had been given, which we think unnecessary to consider. We will, therefore, proceed at once to the principal question in the case. It is contended by complainant, and the court "¡below so held, that the property having once been assessed on account of the laying of the water main in O street, whether that assessment had been rightfully or wrongfully canceled by the city, the same property could not again be assessed for the same pur*286posé. It is also asserted by complainant that, before purchasing the lots, and long after the O street main-was-laid, he procured a certificate from the assessor of the-District, showing that there was, at that time, no- water-main tax assessed against the property. This certificate was in accordance with the facts here shown, since it appears that the assessment had been canceled. If this certificate had been given when every one of the assess-ments in question was standing upon the books of the District, it would have been a bar to any action for the recovery of the tax so assessed. (27 Stat. at L. 37, chap. 74.) If, however, complainant relied upon the prior cancelation, as a bar against a future assessment for the laying of water mains in Decatur street, his position cannot be sustained.

No question has been raised in this case as to the authority of the commissioners of the District of Columbia to lay the water mains in Decatur street, and we assume none can be. The legality of the action of the commissioners in the premises being assumed, the sole question is whether the lots, having been assessed on account of the laying of the main in O street, which assessment was canceled, may be subsequently assessed for the same purpose in another street on which they abut. The act of the legislative assembly of Tune 23, 1873 (Abert & L. Comp. Stat. 548), provides, in part, as follows: “That hereafter, in order to defray the expense, of laying water mains and the erection of fire plugs, there be, and is hereby, levied a special tax of cents per square foot on every lot and part of lot which binds in or touches on any-avenue, street, or alley in which a main water pipe may hereafter be laid and fire .plugs erected, which tax shall be assessed by the collector [water registrar] within thirty days after such water mains and fire plugs shall have been laid and erected, etc.” We think this act, reasonably construed, prohibits the subjection of any property assessed under it to the payment of more than one water-main tax. It logically follows, however, that this limitation can only be applied when a tax has been paid,' and not where it has merely been assessed. All property within the District should contribute its just share to public improvement, but, having once contributed to a specific *287purpose, it should not be called upon to contribute a second time to the same end. Until contribution has been made, we think it cannot claim relief under the statute. No inequity has been done by imposing this duty upon the property in question, on account of the laying of the water mains in Decatur street, instead of in 0 street. It is not claimed that the present assessment is greater than the former one. The fact that the owners of the property have def aulted in the payment, and have allowed the property to be sold for delinquent instalments of the tax, is unfortunate, but it is something which cannot be considered in determining the power of the District to impose this tax.

There is some contention as to the Decatur street mains not being large enough to supply these lots with sufficient water to meet their necessities. If this be true, it can be supplied from the O street main. The property having once contributed its share to the installing of the water system, the duty devolves upon the city to conveniently supply the needs of that property without further contribution on account of laying the mains.

We are unable to agree with the conclusion in the opinion of the learned justice of the court below, where he said: “So far as the record shows, it may be inferred that this reassessment was properly made, and the amount should have been collected, notwithstanding the certificate as to the taxes aforesaid. It was made under an act of Congress that was passed after the complainant bought the ground; and if Congress had the right to authorize the commissioners at that time to levy a reassessment, which I presume it did have, there would seem to be no reason why the lots should not have borne that burden, and that tax have been collected, so that, so far as appears from this case, I am inclined to hold that the lots were properly chargeable with a water-main tax which has been canceled, rightfully or wrongfully, but at any rate voluntarily, by the District authorities. If I am right in this conclusion, under the act of the legislative assembly of June 23, 1873, no further water-main taxes could be rightfully imposed.”

We are of opinion that the case does not turn upon presump*288tions as to the propriety or impropriety of the action of the commissioners of the District, but upon the duty of the property to contribute its share to a public improvement. So long as the ■ legality of the present assessment stands unassailed, and the amount assessed against the property is not more than the amount for which it would have been liable under the 0 street assessment, the complainant cannot be heard in a court of equity to complain. The decree is reversed, with costs, and the court is directed to dismiss the bill. Reversed.