D.C. Code § 8-105.03

(a) Nothing in this subchapter shall be construed as prohibiting any special agreements between WASA and any user of the wastewater system under which wastewater of specific strength or character is accepted into the wastewater system and treated subject to any payments or fees as may be applicable, provided, that:
(1) National categorical pretreatment standards set forth at 40 C.F.R. § 403.6 and prohibited discharge standards set forth at 40 C.F.R. §§ 403.5(a) and (b) shall not be waived, unless such waiver is granted by mechanisms established under the Federal pretreatment regulations (40 C.F.R. § 403 et seq.).
(2) In no case shall a special agreement or waiver of local limits allow for an industrial user to discharge any pollutant which, alone or in combination with other regulated industrial user discharges, would reasonably be expected to exceed the mass loadings determined by WASA as acceptable to the sewage treatment plant based upon considerations of, among other things, interference, pass through, and sludge contamination. WASA may consider other factors (e.g., effect of the discharge on the POTW, future expansion, etc.), as it considers appropriate. In no event shall special agreement or waiver allow the sum of the loadings allocated to all industrial users for any pollutant to exceed the maximum allowable industrial loading set forth in any local limits analysis submitted by WASA and approved by EPA as part of WASA’s pretreatment program.
actors (e.g., effect of the discharge on the POTW, future expansion, etc.), as it considers appropriate. In no event shall special agreement or waiver allow the sum of the loadings allocated to all industrial users for any pollutant to exceed the maximum allowable industrial loading set forth in any local limits analysis submitted by WASA and approved by EPA as part of WASA’s pretreatment program.
(3) WASA may require an industrial user requesting a special agreement or waiver adjusting effluent limitations to submit supporting documentation indicating why the industrial user cannot reasonably expect to meet the effluent limitation contained in its wastewater discharge permit, setting forth an expeditious schedule for achieving compliance with such limitations, and including such other information as WASA may require. In granting any special agreement or waiver WASA may impose time limitations upon any reduced requirements and provide a compliance schedule for achieving compliance. In granting any special agreement or waiver, WASA may impose any other conditions it considers necessary to implement the purposes of this section.
(4) If granting a special agreement or waiver would result in increased costs to WASA, (e.g., treatment, monitoring, sludge disposal costs), WASA may condition the special agreement or waiver upon the agreement of the industrial user to pay those costs, and to provide security adequate in the judgment of WASA to assure payment of those costs.
(b) All special agreements or waivers shall be requested and granted in writing.