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Tap water quality report

D.C. Water and Sewer Authority

EPA monitoring tested this supplier for 41 contaminants and detected 10. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

41
contaminants tested
10
detected
632,323
people served
32
health-based violations
Water source
SWP
Ownership
Local government
Counties served
District of Columbia

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

32
health-based violations
82
violations on file
0
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 2004-10-01
TT Health-based Resolved 2004-10-01
MCL Health-based Resolved 2004-09-01 → 2004-09-30
TT Health-based Resolved 2002-10-01
TT Health-based Resolved 2002-10-01
TT Health-based Resolved 2002-10-01
TT Health-based Resolved 2002-10-01
TT Health-based Resolved 2001-07-01
TT Health-based Resolved 2001-07-01
TT Health-based Resolved 2001-07-01

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
Pfpea 0.0047 µg/L 2/8 2024
Pfhxa 0.0031 µg/L 1/8 2024

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Total Haloacetic Acids (HAA5)
48.9 µg/L 82%
of the EPA limit 60 µg/L
109/109 SYR4 2015–2017
TTHM
82 µg/L 102%
of the EPA limit, in the worst sample — 80 µg/L
107/107 SYR4 2015–2017
Lead
0.0020 mg/L 13%
of the EPA limit 0.0150 mg/L
59/59 LCR 2025
Bromodichloromethane
21.2 µg/L
No EPA limit set
4/4 SYR4 2016
Chloroform
48.1 µg/L
No EPA limit set
4/4 SYR4 2016
Dibromochloromethane
5.9 µg/L
No EPA limit set
4/4 SYR4 2016
Dibromoacetic Acid
2.5 µg/L
No EPA limit set
1/1 SYR4 2016
Monobromoacetic Acid
8.1 µg/L
No EPA limit set
1/1 SYR4 2016
31 contaminants tested, none detected
11Cl-PF3OUdS4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaBromoformDichloroacetic AcidHfpo-DaMonochloroacetic AcidNetfosaaNfdhaNmefosaaPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpesPftaPftrdaPfunaLithium

Utility contact

Contact
SCHMELLING, MAUREEN
Phone
202-364-3131
Email
maureen.schmelling@dcwater.com

Frequently asked questions about D.C. Water and Sewer Authority

Is D.C. Water and Sewer Authority tap water safe to drink?

EPA monitoring detected 10 contaminants in D.C. Water and Sewer Authority's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in D.C. Water and Sewer Authority's water?

EPA monitoring detected Total Haloacetic Acids (HAA5), TTHM, Lead, Bromodichloromethane, Chloroform, and others. The full list with the level and data source for each is above.

How many people does D.C. Water and Sewer Authority serve?

D.C. Water and Sewer Authority reports serving 632,323 people in DC, per its EPA record.

Has D.C. Water and Sewer Authority had any water quality violations?

The EPA has 82 violations on file for D.C. Water and Sewer Authority, of which 32 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.