Drinking water quality · 2023
· Verified
What's in Washington Dc, DC tap water
30 contaminants were measured in the Washington Dc, DC water system's 2023 annual report. Each is shown below against its federal limit — 1 sit at or above that limit.
- Reporting year
- 2023
- Contaminants measured
- 30
- Over federal limit
- 1
- Approaching the limit
- 0
- Worst contaminant
- PFOS
- Service area
- DC
PFAS — EPA UCMR5 (2023–2025)
2 PFAS compounds detected in Washington Dc, DC
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFHxA
● Detected (no federal limit)below national p90 (12.190000000000003 ng/L across detecting U.S. systems)
PFPeA
● Detected (no federal limit)below national p90 (15.95999999999999 ng/L across detecting U.S. systems)
Where your water comes from · EPA SDWIS
Washington Dc, DC buys its drinking water from WASHINGTON AQUEDUCT DIVISION..
Source
Treatment
Distribution
Also buys water from WASHINGTON AQUEDUCT DIVISION..
Historical readings · EPA Six-Year Review (2012–2019)
1 contaminant historically over EPA limits in Washington Dc, DC
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
TTHM worst: 2017 | 0.082 mg/L 1.0× | 0.08 mg/L | '15'16'17 |
HAA5 worst: 2017 | 0.0489 mg/L 82% | 0.06 mg/L | '15'16'17 |
DBAA worst: 2016 | 0.0025 mg/L | — | '16 |
MBAA worst: 2016 | 0.0081 mg/L | — | '16 |
BROMODICHLOROMETHANE worst: 2016 | 0.0212 mg/L | — | '16 |
CHLOROFORM worst: 2016 | 0.0481 mg/L | — | '16 |
DIBROMOCHLOROMETHANE worst: 2016 | 0.0059 mg/L | — | '16 |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PFOSPerfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. | 2.1AverageSystem-wide | 1.9MCL | At or above the limit |
| PFOAPerfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. | 1.5AverageSystem-wide | 1.9MCL | Within the limit |
| Perfluorohexanesulfonic acidPerfluorohexanesulfonic acid, a PFAS 'forever chemical.' | 0.2AverageSystem-wide | 1.9MCL | Within the limit |
| PFAS | 0.001AverageSystem-wide | None set | Detected — no federal limit |
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 3 mg/LRunning annual avgSystem-wide | 4 mg/LMCLG | Within the limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 2 mg/LRangeDC Drinking Water | 10 mg/LMCLG | Within the limit |
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.7 mg/LMaximumDC Drinking Water | 4 mg/LMCLG | Within the limit |
| Ammonia | 1 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| ChlorideA naturally occurring salt compound. | 32 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| SulfateA naturally occurring mineral from rock and soil. | 47 mg/LAverageSystem-wide | None set | Detected — no federal limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| BariumA metal from erosion of natural deposits and industrial discharge. | 0.04 mg/LRangeDC Drinking Water | 2 mg/LMCLG | Within the limit |
| AluminumA common element sometimes used as a treatment coagulant. | 39 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| ArsenicA naturally occurring element that also enters water from industry and agriculture. | 0.4 ug/LMaximumDC Drinking Water | 0 ug/LMCLG | Detected — no federal limit |
| CalciumA naturally occurring mineral that contributes to water hardness. | 39 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| IronA naturally occurring metal common in groundwater. | Not detected ug/LAverageSystem-wide | None set | Detected — no federal limit |
| LithiumA naturally occurring element found in some groundwater. | 2 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| MagnesiumA naturally occurring mineral that contributes to water hardness. | 9 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| ManganeseA naturally occurring metal from soil and rock. | 0.3 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| NickelA metal from natural deposits and industrial discharge. | 0.3 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| PotassiumA naturally occurring mineral from rock and soil. | 3 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 22 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| Strontium | 187 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| Vanadium | Not detected ug/LAverageSystem-wide | None set | Detected — no federal limit |
| ZincA naturally occurring metal that can also enter water from corroding pipes. | Not detected ug/LAverageSystem-wide | None set | Detected — no federal limit |
VOCs & pesticides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Dalapon | 1 ug/LRangeSystem-wide | 200 ug/LMCLG | Within the limit |
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PerchlorateA chemical used in rocket fuel and fireworks that can also form during disinfection. | 0.2 ug/LAverageSystem-wide | None set | Detected — no federal limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| HardnessA measure of dissolved calcium and magnesium minerals. | 8AverageSystem-wide | None set | Detected — no federal limit |
| TOCTotal organic carbon — a measure of organic material dissolved in the water. | 1.37Reported levelDC Drinking Water | None set | Detected — no federal limit |
People also ask about Washington Dc, DC's water
+Is Washington Dc, DC tap water safe to drink in 2023?
The 2023 Consumer Confidence Report for the Washington Dc, DC water utility lists 1 contaminant at or above the federal limit: PFOS. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in Washington Dc, DC tap water?
30 contaminants were measured in Washington Dc, DC's 2023 Consumer Confidence Report, spanning metals, inorganic chemicals, and pfas ("forever chemicals"). 11 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in Washington Dc, DC tap water?
One contaminant in Washington Dc, DC's 2023 report sits at or above the federal limit: PFOS (1.1× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in Washington Dc, DC tap water?
The contaminant with the highest measured value relative to its federal limit in the 2023 report is PFOS, at 1.1× the federal threshold. It belongs to the pfas ("forever chemicals") family of contaminants.
+Where does the data on this page come from?
Every value is transcribed from Washington Dc, DC's 2023 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Washington Dc, DC's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2023 report; a new report will replace it once the utility publishes its next annual update.