Section 34-2107 - Methods of determination of sanitary sewer service charges(a) The sanitary sewer service charges established under the authority of this subchapter shall be based on the following: (1) A billing methodology which takes into account both the water consumption of, and water service to, a property and the amount of impervious surface on a property that either prevents or retards the entry of water into the ground as occurring under natural conditions, or that causes water to run off the surface in greater quantities or at an increased rate of flow, relative to the flow present under natural conditions. For the purposes of this paragraph, the term "surface" shall include rooftops, footprints of patios, driveways, private streets, other paved areas, athletic courts and swimming pools, and any path or walkway that is covered by impervious material.(3)(A) For any unimproved real property under construction that discharges groundwater into a District-owned sanitary sewer, or combined sewer, or for any real property using water, part of which is from a source or sources other than the District water supply system, the real property owner shall pay a sanitary sewer service charge separate from and in addition to any sanitary sewer service charge levied in paragraphs (1) or (2) of this subsection. For any improved real property that discharges groundwater into a District-owned sanitary or combined sewer, the real property owner shall not be subject to payment of a separate and additional charge for discharges of groundwater, but shall pay for discharges of cooling water into a District-owned sanitary of combined sewer that are derived from a source or sources other than the District water supply system.(B)(i) For unimproved real property under construction the separate and additional sanitary sewer service charge shall apply to and be measured by the quantity of water that is derived from the groundwater and is discharged into the District sanitary or combined sewer system.(ii) For improved real property, the separate and additional sanitary sewer service charge shall apply to and be measured by the quantity of water that is derived from the cooling water and is discharged into the District sanitary or combined sewer system.(iii) For real property using water from a source or sources other than the District water supply system, such separate and additional charge shall be measured by the quantity of water from the source or sources other than the District water supply system discharged into the District sanitary or combined sewer system from the property.(C) Unless the Mayor determines that it is not practicable, the owner of the real property shall install and maintain, at a location approved by the Mayor and without cost to the District, any sanitary meter or device necessary to measure the quantity of groundwater, cooling water, or water from other than the District water supply system that is discharged into the District's sanitary sewers.(D) For purposes of this section, the determination made by the Mayor pursuant to Chapter 8 of Title 47 as to whether property is improved or unimproved shall apply.(4) Wherever a property upon which a sanitary sewer service charge is imposed uses water from the water supply system of the District for an industrial or commercial purpose in such manner that the water so used is not discharged into the sanitary sewage works of the District, the quantity of water so used and not discharged into the sanitary sewage works of the District may be excluded in determining the sanitary sewer service charge on such property, if such exclusion is previously requested in writing by the owner or occupant thereof. Upon such request, the quantity of water so used and not discharged into the sanitary sewage works of the District shall be measured by a device or devices approved by the Mayor, installed and maintained without cost to the District, and the sanitary sewer service charge to be imposed on such property shall be the amount which would have been charged such property if the amount of water so used and not discharged into the sanitary sewage works of the District had not been included in the amount of water used by such property; provided, that all water from the water supply system of the District used by such property shall be paid for at established rates, whether or not such water is discharged into the sanitary sewage works of the District. Where in the opinion of the Mayor, it is not practicable to install a measuring device to determine continuously the quantity of water used for such industrial or commercial purposes and not discharged into the sanitary sewage works of the District, the Mayor shall determine periodically, in such manner and by such methods as the Mayor may prescribe, the quantity of water from the water supply system of the District discharged into the sanitary sewage works of the District, and the sanitary sewer service charge shall be based on such estimated quantity of water at the percentage authorized by this paragraph. Any dispute as to such estimated amount shall be decided by the Mayor and such decision shall be final; and in the event the owner or occupant fails to furnish and maintain such measuring devices or to facilitate the periodic determinations by the Mayor as prescribed herein, then the privilege of excluding some portion of the water used from the District water supply system from the charges for sanitary sewer service shall be forfeited and the charges for sanitary sewer service shall be based on the full amount of the water used from the District water supply system.(b) Notwithstanding the provisions of subsection (a), the Council of the District of Columbia is authorized, in its discretion, from time to time to establish 1 or more sanitary sewer service charges at such amount as the Council, on the basis of a recommendation made by the Mayor, finds it necessary to meet the expense to the District of furnishing sanitary sewer services, including debt retirement.(c) Any owner or occupant of a property that is assessed an impervious surface fee has a right to an appeal under § 34-2305.May 18, 1954, 68 Stat. 106, ch. 218, title II, §207; Mar. 2, 1962, 76 Stat. 18, Pub. L. 87-408, § 502; Jan. 5, 1971, 84 Stat. 1931, Pub. L. 91-650, title I, § 105 (b); June 13, 1990, D.C. Law 8-136, § 2(d), 37 DCR 2620; Oct. 1, 2002, D.C. Law 14-190, § 3902, 49 DCR 6968; Mar. 25, 2009, D.C. Law 17-370, § 2, 56 DCR 1350.