All 3 systems met the sampling requirement for a yearly average. Of those systems, 0 had at least one yearly average above an EPA comparison level and 3 did not.
EPA-based study benchmark: a fixed, unrounded research cutoff used to reproduce EPA’s final UCMR 5 technical-assistance classification based on the April 2024 federal levels. It is not a current federal or state standard. The label does not determine compliance, household exposure, or health risk.
State rules: The labels on this page use fixed research cutoffs based on the April 2024 federal levels. District of Columbia may use different current standards or guidance. These UCMR 5 results do not determine current federal or state compliance. Find the official District of Columbia drinking-water program →
Find your water system
A ZIP code finds possible public water systems for an area; it cannot identify the supplier for a specific home. Confirm the provider using a water bill or utility record.
System counts in District of Columbia
Each count shows how many included water systems had a yearly average above the named EPA comparison level.
| EPA rounding cutoff | Systems above comparison level | Water systems included | Percent |
|---|---|---|---|
| PFOA: 4 ppt level; unrounded average ≥4.05 ppt after applying EPA rounding | 0 | 3 | 0.0% |
| PFOS: 4 ppt level; unrounded average ≥4.05 ppt after applying EPA rounding | 0 | 3 | 0.0% |
| PFHxS: 10 ppt level; unrounded average ≥15 ppt after applying EPA rounding | 0 | 3 | 0.0% |
| PFNA: 10 ppt level; unrounded average ≥15 ppt after applying EPA rounding | 0 | 3 | 0.0% |
| HFPO-DA: 10 ppt level; unrounded average ≥15 ppt after applying EPA rounding | 0 | 3 | 0.0% |
| Hazard Index: 1 level; unrounded index ≥1.5 and at least two detected components | 0 | 3 | 0.0% |
Community water systems with complete monitoring
“Complete monitoring” means at least one sampling location had every required sample needed to calculate a yearly average. It does not mean every location or home was tested. Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | EPA comparison result |
|---|---|---|---|---|---|
| D.C. WATER AND SEWER AUTHORITY | DC0000002 | 632,323 | Surface water purchased | 2 | No available average above comparison levels |
| JOINT BASE ANACOSTIA - BOLLING | DC0000004 | 19,312 | Surface water purchased | 4 | No available average above comparison levels |
| NAVAL STATION WASHINGTON - WNY | DC0000003 | 16,800 | Surface water purchased | 1 | No available average above comparison levels |
What is included
Each active community water system with enough required samples for a yearly average is counted once, even if it is linked with several ZIP codes. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system.