D.C. Code § 34-2405.02
For laying or constructing water mains in the District of Columbia assessments shall be levied at the rate of $3 per linear front foot against all lots or land abutting upon that part of the street, avenue, road, or alley in which a water main shall be laid, and that for laying or constructing service sewers in the District of Columbia assessments shall be levied at the rate of $4 per linear front foot against all lots or land abutting upon that part of the street, avenue, road, or alley in which a sewer shall be laid; provided, that assessments for water mains and service sewers in the case of lots or parcels of land not more than 100 feet in depth shall be levied upon the fronts or rears of such lots or parcels of land, and not upon both the fronts and rears of such lots or parcels of land; but lots or parcels of land more than 100 feet in depth, except corner lots, shall be assessed upon both their fronts and rears when water mains or service sewers are laid abutting the same; provided, that corner lots shall be assessed for water mains and service sewers only on their short fronts with a depth of not exceeding 100 feet; any excess of the other front over 100 feet shall be subject to assessment, as hereinbefore provided; provided, that the areas of all lots or parcels of land which have been assessed for water mains by the square foot under any previous act of Congress, or of the late legislative assembly of the District of Columbia, shall not be again assessed for water mains; provided further, that when the Mayor of the District of Columbia shall deem it advantageous to lay water mains or service sewers on each side of any street, avenue, road, or alley assessments shall be levied at the rate, within the time and in the manner in this section provided for, against the lots abutting the side of the street, avenue, road, or alley in which the water main or service sewer is laid.
D.C. Code § 34-2405.02