DC Water and Sewer Authority

The DC Water and Sewer Authority serves approximately 672,000 residents in the District of Columbia while providing wholesale water to an additional 1.1 million customers across suburban Maryland and Northern Virginia jurisdictions — making it one of the largest combined water and wastewater utilities in the Mid-Atlantic region. The authority operates under a dual federal-local regulatory framework that distinguishes it from most municipal utilities in the United States, a structural complexity that directly affects rate-setting, compliance obligations, and infrastructure investment cycles.

DC Water (formally the District of Columbia Water and Sewer Authority) was established under D.C. Code § 34-2202.01 as an independent authority of the District government (according to DC Water). The governing board consists of 11 members: 6 representing the District of Columbia and 5 representing the suburban wholesale customers — Montgomery County, Prince George's County, Fairfax Water, the City of Falls Church, and Loudoun Water. This multi-jurisdictional board structure reflects the regional wholesale agreements that extend DC Water's service footprint well beyond the District boundary.

The authority is not a subordinate agency of the DC government. It issues its own revenue bonds, sets rates independently, and enters contracts without District Council approval, though its enabling statute places it under oversight from the DC Government Office of People's Counsel for retail ratemaking proceedings.

Water Supply Source

DC Water draws its raw water supply from the Potomac River, supplemented by the Washington Aqueduct — a federal facility operated by the U.S. Army Corps of Engineers. The Washington Aqueduct treats Potomac River water at two facilities, the Dalecarlia Water Treatment Plant and the McMillan Sand Filtration Site, before delivering finished water to DC Water's distribution system. This federal-to-local handoff is a structural feature unique to Washington's water supply chain.

The USGS Maryland-Delaware-DC Water Science Center monitors streamflow and water quality conditions in the Potomac basin, providing the hydrological data that informs both treatment operations and drought contingency planning.

Regulatory Framework

DC Water operates under two principal federal statutes administered by the EPA.

The Safe Drinking Water Act (SDWA) governs finished drinking water quality. Under SDWA, DC Water must meet National Primary Drinking Water Regulations, submit Consumer Confidence Reports annually, and comply with the Lead and Copper Rule — a requirement that has driven significant pipe replacement activity in the District since the early 2000s lead contamination findings.

The Clean Water Act (CWA) governs wastewater discharge. DC Water's Blue Plains Advanced Wastewater Treatment Plant, located at 5000 Overlook Avenue SW, is one of the largest advanced wastewater treatment facilities in the world, processing up to 370 million gallons per day at peak capacity. Blue Plains discharges treated effluent to the Potomac River under a National Pollutant Discharge Elimination System (NPDES) permit issued pursuant to CWA Section 402. Permit conditions, monitoring data, and compliance history are publicly searchable through EPA ECHO.

Specific numerical effluent limits — including biochemical oxygen demand (BOD), total suspended solids (TSS), total nitrogen, and phosphorus thresholds — are established in the facility's NPDES permit. Regulatory limits for water contaminants are codified in 40 CFR Parts 141–143 under EPA's drinking water standards framework.

The EPA Drinking Water and Wastewater Utilities portal provides the national policy context within which DC Water's operating permits are evaluated, including guidance on affordability frameworks and asset management standards.

Infrastructure: The DC Clean Rivers Project

DC Water's most consequential capital program is the DC Clean Rivers Project, a long-term control plan to reduce combined sewer overflows (CSOs) into the Anacostia River, Rock Creek, and the Potomac River. The project is governed by a consent decree entered in the U.S. District Court for the District of Columbia.

The centerpiece of the project is a system of deep rock tunnels — the Anacostia River Tunnel, the Potomac River Tunnel, and the Northeast Boundary Tunnel — designed to capture combined sewage during storm events before it overflows into waterways. The Northeast Boundary Tunnel alone stretches approximately 3 miles and sits 100 feet below ground. Total projected program cost exceeds $2.7 billion (according to DC Water). Tunnel storage capacity across the full system is approximately 157 million gallons.

Rates and Affordability

DC Water sets rates through a board-approved process that must recover the full cost of service, including debt service on capital bonds. Retail customers in the District pay volumetric rates for water consumption, a separate charge for wastewater, and an impervious surface charge tied to stormwater management. The Office of People's Counsel represents residential ratepayers in formal rate proceedings and has intervened in multiple rate cases to challenge proposed increases.

The Congressional Research Service has analyzed water infrastructure funding nationally, noting that federal grants for drinking water and wastewater infrastructure have not kept pace with the estimated $655 billion in national investment needs identified by EPA's infrastructure gap assessments — a fiscal pressure that pushes capital costs onto ratepayers through bond-financed rate structures like DC Water's.

Environmental Compliance and Monitoring

DC Water's compliance status across both drinking water and wastewater programs is subject to continuous federal monitoring. Violations, enforcement actions, and inspection records are publicly accessible through EPA ECHO. The authority files discharge monitoring reports (DMRs) with EPA Region 3 on a monthly basis for Blue Plains operations.

References

The law belongs to the people. Georgia v. Public.Resource.Org, 590 U.S. (2020)

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