State drinking water records

District of Columbia drinking water systems

4 community water systems serve District of Columbia and are listed below under 1 county and on the pages of 1 city or town. Their own population figures add up to 667,325 people, a sum that counts people twice where one system sells water to another.

2 of them had at least one health-based violation in the last 10 years. 1 system still has one unresolved.

4 rely mainly on surface water, counting water bought from other systems.

Their lead service line inventories list 16,935 lead lines, 220 galvanized lines that must be replaced and 13,427 lines of unknown material.

2 systems have no service area map from EPA and are placed by mailing address.

Community water systems

4

People served, sum of each system's own figure

667,325

Systems with a health-based violation, last 10 years

2

Systems with one unresolved

1

Lead service lines in inventories

16,935

Counties

1 county

Each county counts the systems whose service area map reaches it. Systems placed only by a mailing address are listed on the county pages but not counted here.

County	Systems	People served	With a health-based violation, 10 years	With one unresolved
District of Columbia	2	651,635	1	1

Largest systems

System	Main county	People served	Main source	Health-based violations, 10 years	Unresolved	Lead lines
D.C. Water and Sewer Authority	District of Columbia	632,323	Purchased surface water	0	0	16,935
Joint Base Anacostia - Bolling	District of Columbia	19,312	Purchased surface water	7	2	0
Naval Station Washington - Wny	District of Columbia	15,690	Purchased surface water	4	0	0
Washington Aqueduct Division.	District of Columbia	Not reported	Surface water	0	0	0

Systems with unresolved health-based violations

1 system

System	Main county	People served	Main source	Health-based violations, 10 years	Unresolved	Lead lines
Joint Base Anacostia - Bolling	District of Columbia	19,312	Purchased surface water	7	2	0

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Counties come from the counties EPA lists each system serving, matched to 2024 Census counties; where EPA lists none, from the county coded in the system's ID, its service area map, or its mailing address. A county holding at least a fifth of a system's service area map is added when at least a fifth of that map lies in those counties. Towns are the ones EPA lists and the Census places such a map covers, always inside those counties. In New England, where EPA's town names a whole Town, it is not matched to the village of the same name. A system is not listed in a county holding less than a fifth of its map, or in a county or town its map reaches when the map lies mostly outside the counties EPA lists, so a page can leave out a system that serves part of the area. Methodology and limitations