Tap Water Quality Report
Tap water quality in Washington, District of Columbia
Tap water in Washington, District of Columbia receives a grade of D (66/100) from TapWaterSafety.org. It's served by Washington Municipal Water System. The most significant water quality concerns are: Lead detected in source water; Haloacetic Acids (HAA5) significantly above health guideline; Chromium-6 detected. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database, and Washington's published Consumer Confidence Report.
What's in Washington's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving Washington.
Lead detected in source water
Severe concernLead detected at 4.4 ppb. EWG considers no level of lead safe; EPA's action level is 15 ppb.
Haloacetic Acids (HAA5) significantly above health guideline
Moderate concernHaloacetic Acids (HAA5) detected at 25.0 ppb, 250x above the EWG health guideline of 0.1 ppb.
Chromium-6 detected
Moderate concernChromium-6 detected at 0.15 ppb.
Recommended filters for Washington
Filters matched to the specific contaminants in Washington's water supply.
NSF/ANSI 53 certified for lead removal
$80-$750NSF 53 is the gold standard certification for lead removal. Required when lead is a documented concern.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Reverse Osmosis
$249-$750Chromium-6 requires reverse osmosis for reliable removal. Standard carbon filters do not address it.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in Washington's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic Acids (HAA5) Disinfection byproduct |
25.0 ppb | 0.1 | 60 | 60 | — | — | 2023 | 250× over |
| Total Trihalomethanes (TTHMs) Disinfection byproduct |
18.3 ppb | 0.6 | 80 | 100 | — | — | 2022 | 31× over |
| Nitrate Inorganic |
1.43 mg/L | 0.14 | 10 | 11.3 | 11.3 | 10 | 2022 | 10× over |
| Chromium-6 (Hexavalent) Heavy metal |
0.183 ppb | 0.02 | — | — | — | 0.02 | 2023 | 9.2× over |
| Lead Heavy metal |
5.16 ppb | 0 | 15 | 5 | 10 | 0.2 | 2023 | Fails EU |
| Contaminant | Detected (2023) | EWG | EPA | EU DWD | WHO | CA PHG | Status |
|---|---|---|---|---|---|---|---|
| Haloacetic Acids (HAA5) Disinfection byproduct |
25.0 ppb | 0.1 | 60 | 60 | — | — | 250× over |
| Chromium-6 (Hexavalent) Heavy metal |
0.183 ppb | 0.02 | — | — | — | 0.02 | 9.2× over |
| Lead Heavy metal |
5.16 ppb | 0 | 15 | 5 | 10 | 0.2 | Fails EU |
| Contaminant | Detected (2022) | EWG | EPA | EU DWD | WHO | CA PHG | Status |
|---|---|---|---|---|---|---|---|
| Total Trihalomethanes (TTHMs) Disinfection byproduct |
18.3 ppb | 0.6 | 80 | 100 | — | — | 31× over |
| Nitrate Inorganic |
1.43 mg/L | 0.14 | 10 | 11.3 | 11.3 | 10 | 10× over |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from Washington Municipal Water System.
General Contact
Water Quality Contact
For questions about contaminants or test results.