DC Water (District of Columbia Water and Sewer Authority)

About the Utility

DC Water, the District of Columbia Water and Sewer Authority, provides retail drinking water and wastewater services in the District and wholesale wastewater treatment at Blue Plains for suburban counties in Maryland and Virginia. Its rates are set by its own Board of Directors under the Authority statute rather than by the District’s Public Service Commission. The Board has 11 principal members drawn from the District and from Montgomery, Prince George’s and Fairfax counties. The authority employed 1,128 people and served 127,562 customer accounts in FY 2025, and S&P has rated its senior-lien debt AAA for 10 consecutive years.

Water System

DC Water distributes drinking water it does not treat itself: the Washington Aqueduct withdraws about 140 million gallons a day from intakes at Great Falls and Little Falls, and DC Water carries it across the District. Its quality results complied with all EPA drinking water standards in 2024. Two constraints dominate: the District depends on that single source and once came within 30 minutes of exhausting its supply. Lead is the other: more than 42,000 service lines contain lead or galvanized-iron pipe, which DC Water aims to remove by 2030. Water billed was 67.17% of water pumped in the latest fiscal year.

Wastewater System

Blue Plains treats close to 300 million gallons of wastewater a day on average and serves the District and neighbouring counties in Maryland and Virginia. Its treatment train runs from primary and secondary treatment through denitrification and multimedia filtration. Solids pass through the Bailey Bioenergy Facility, which generates up to 10 megawatts and produces Class A biosolids sold as Bloom. Combined sewer overflows are the central performance issue, and tunnels are now delivering results: overflows to the Anacostia River have fallen by 90 percent since March 2018.

Investment & Priorities

Investment is led by the Clean Rivers Project, required by a consent decree with EPA whose final compliance date is 2030. The Northeast Boundary Tunnel entered operation in 2023, and the $819 million Potomac River Tunnel is projected for completion in 2030. Lead Free DC adds an estimated $1.8 billion programme. S&P credits DC Water with executing a $9.7 billion ten-year capital plan, financed partly through green and century bonds and a federal WIFIA loan.

Sustainability & Resilience

Supply resilience is now an explicit priority. Pure Water DC, launched in November 2025, is exploring advanced water reuse at Blue Plains as a second drinking water source, backed by $21 million in seed funding. Affordability is the counterweight to heavy investment: bills have risen steadily, and a multi-tier Customer Assistance Program cushions low-income households as the authority proposes a further 6.6 percent increase for the next fiscal year.

Key Challenges

1. Delivering the Potomac River Tunnel and remaining Clean Rivers works by the 2030 compliance date.
2. Removing all lead service lines in the District by 2030 within an estimated $1.8 billion programme.
3. Securing a second drinking water source to reduce dependence on the Washington Aqueduct.
4. Maintaining affordability as proposed rate increases follow a decade of rising bills.

Major Projects