District of Columbia Water Quality
Drinking water data for all 1 counties.
Avg SDWIS Compliance Index
70.3
Most Common Five-Year SDWIS Compliance Band
A
Counties with Data
1
of 1 total
County water atlas
District of Columbia water signals by county
A state-level 2.5D view across drinking-water compliance, watershed impairment, monitoring density, and streamflow snapshot context. Pin any county, switch layers, then use the lens controls to compare index ranges, recorded violation rates, or impaired watersheds without leaving the page.
Counties
1
Avg SDWIS index
70.3
Watersheds
0
ATTAINS counties
Monitoring
1
1 fresh USGS snapshots
State atlas layers combine EPA SDWIS health-based violations, EPA ATTAINS 303(d) impairment assessments, EPA Water Quality Portal monitoring sites, and representative USGS NWIS streamflow gauges. Streamflow values appear only for fresh pipeline snapshots, not as a continuously updated stream. County pages include the observation time and year.
Multi-source coverage in District of Columbia
Beyond Drinking Water
EPA SDWIS
1/ 1
counties with drinking-water compliance data
5 health violations statewide (5yr)
EPA ATTAINS
—
No §303(d) assessments yet for District of Columbia
EPA WQP
134
monitoring sites across 1 counties
74,604 total readings (5yr window)
USGS NWIS
1
counties with a fresh pipeline snapshot
0 above1 below
State atlas notes
What stands out in District of Columbia
County water quality is not one number. The strongest read comes from comparing drinking-water compliance against watershed impairment, monitoring density, and streamflow context. Use these signals as a starting point, then open any county profile for source-level detail.
Compliance spread
District of Columbia has the highest value in the published state SDWIS Compliance Index table at 70.3/100, while District of Columbia has the lowest at 70.3/100. That is a 0.0 point gap inside one state.
Zero health violations
0
3+ health violations
1
Monitoring hubs
Lowest flow reads
Highest fresh streamflow pipeline snapshots: District of Columbia (45%, observation 2026). These are source-data observations, not household tap-water conclusions.
All District of Columbia Counties
| County | SDWIS Compliance Index |
|---|---|
| District of Columbia | 70.3 |
Frequently Asked Questions
Which District of Columbia county has the highest SDWIS Compliance Index?
What does the Five-Year SDWIS Compliance Band mean?
Which USGS streamflow records are shown across District of Columbia?
Where can District of Columbia residents find current official information?
What does Water Quality Portal monitoring volume show in District of Columbia?
Data Sources
Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. The WaterByCounty SDWIS Compliance Index reflects the recorded rate and is not an EPA score.
Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.