County water report

District of Columbia Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for District of Columbia, District of Columbia.

Water grade

Water score

69.3

State rank

of 1

Health violations

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

73,028 recent measurements

Live streamflow

58%

ROCK CREEK AT JOYCE RD WASHINGTON, DC

Water at a glance

Key Water Indicators for District of Columbia

EPA SDWIS

Safety Grade

Score: 69.3 / 100

EPA SDWIS

Active Violations

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

58% of mean

ROCK CREEK AT JOYCE RD WASHINGTON, DC

EPA WQP

Monitoring Sites

73,028 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

69.3/100

Health violations

Health-based violations

Violations per 100K served

1.3

Population-normalized SDWIS rate

Data center water stress

District of Columbia has 1 facility in the DCWSI dataset.

ByCounty's DCWSI ranks this county #1040 nationally by combining its water score with mapped data center density.

DCWSI

41.6

0-100 index

Facility count

0.0 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

+19.3

Compared with US county median

Named operators

CoreSite

Mapped facilities

CoreSite DC1
CoreSite
OSM

See the District of Columbia data-center report Review methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in District of Columbia.

Facility size: 100 MW

1 MW1,000 MW

Cooling type

Utilization: 70%

40%100%

799K gallons/dayHigh Impact

Your facility would use 467.1% of this county's industrial water baseline. Verify water rights and long-term drought projections before committing.

467.1% of county industrial baseline

Based on USGS 2020 water-use data and EPA-standard cooling intensity constants. Not a substitute for site-specific water rights analysis.

Editorial analysis

Understanding District of Columbia’s Water

Drinking Water Quality Overview

EPA SDWIS

District of Columbia earns a B grade for drinking water quality, scoring 69.3 out of 100. Over the past five years, EPA SDWIS records 9 health-based violations — a pattern that public water utilities are required to disclose and correct.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T15:05:00.000-04:00) puts ROCK CREEK at 47.3 cfs — well below its long-term average at 58% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. District of Columbia has extensive coverage with 94 active monitoring sites with 73,028 recent measurements on record. Predominant monitoring categories include physical and nutrient. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for District of Columbia

Water Verdict

District of Columbia, District of Columbia receives a fair water quality assessment with a grade of B and a score of 69.3 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring. The county's primary USGS gauge drains roughly 64 square miles of upstream watershed, giving local source waters a regional footprint. At the most recent USGS reading, local streamflow was below its historical mean at 58.3% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for District of Columbia, District of Columbia show 9 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 1.3 violations per 100,000 people served, this rate is relatively low compared to many U.S. counties. This compliance record sits alongside an unusually deep monitoring archive: 73,028 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water in District of Columbia meets baseline safety standards, though the compliance record shows some violations worth watching. District of Columbia's drinking-water compliance score is 69.3 out of 100. The violation rate for District of Columbia is 1.3 per 100,000 people served. Running tap water for 30 seconds before drinking can reduce any localized lead exposure from household plumbing. Requesting your utility's most recent Consumer Confidence Report is the fastest way to identify which specific contaminants were flagged. With 94 active water-quality monitoring sites in District of Columbia, data coverage is strong. A pipeline streamflow snapshot from the ROCK CREEK gauge is also available on this page.

Regional Context

District of Columbia has water quality close to the average county in District of Columbia. Its water score is within 0 points of the state average, meaning its overall water system performance is broadly representative of District of Columbia as a whole.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in District of Columbia's water environment

Official EPA Resources for District of Columbia

EPA How's My Waterway

Interactive watershed health data for District of Columbia

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for District of Columbia

Consumer Confidence Reports (DC)

Annual water quality reports from utilities in District of Columbia

Past 5 years

Water Quality Monitoring

Monitoring Sites

Active in the past 5 years

Measurements Recorded

73K

73,028 total readings

Most Measured

Physical
Nutrient
Microbiological

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

47.3cfs

May 14, 7:05 PM UTC

vs Long-Term Average

58%

Well below typical

Primary Streamgage

ROCK CREEK AT JOYCE RD WASHINGTON, DC

USGS site: 01648010
Drainage area: 63.7 sq mi
Long-term mean: 81.2 cfs

One representative streamgage (the one with the largest drainage area in the county). Many counties have multiple gauges; this view summarizes the primary one. The long-term mean is the full-record annual average; the percent-of-typical value compares the latest reading against that average.

Free tool

Estimate Your Water Costs

Water Cost Estimate

Household size

3 people · ~225 gal/day

Filter type

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for District of Columbia:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

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Frequently Asked Questions

What is the water quality in District of Columbia, District of Columbia?

District of Columbia, District of Columbia has a drinking-water quality grade of B with a score of 69.3/100, based on EPA SDWIS compliance data. The county has 9 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.

Are there any water violations in District of Columbia?

District of Columbia has 9 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Violations may have been resolved — check with your local water utility for current status.

How much water-quality monitoring happens in District of Columbia?

EPA's Water Quality Portal records 73,028 measurements from 94 monitoring sites in District of Columbia over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Microbiological. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.

What's happening with rivers in District of Columbia right now?

District of Columbia's primary USGS streamgage on the ROCK CREEK has a pipeline snapshot of 47.3 cubic feet per second — 58% of the long-term mean of 81.15 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.

How does District of Columbia water compare to the District of Columbia average?

District of Columbia's SDWIS water quality score of 69.3/100 is equal to the District of Columbia state average of 69.3. The average water quality grade across District of Columbia is C, based on data from 1 counties with available SDWIS data.

Is tap water safe to drink in District of Columbia?

Based on EPA SDWIS data, District of Columbia has a water quality grade of B (69.3/100). This indicates good to excellent water quality with strong SDWIS compliance. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).

Why does District of Columbia have so many water violations?

District of Columbia has 9 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.

How does District of Columbia rank for water quality in District of Columbia?

District of Columbia ranks #1 out of 1 counties in District of Columbia by SDWIS water quality score (1 = best). With a score of 69.3/100, it falls in the top third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP), federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

Live streamflow from the USGS National Water Information System (NWIS), continuous discharge measurements from the largest-drainage gauge in each county, compared against the full-record long-term annual mean.

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.

By Evan Brooks, Data EditorUpdated May 14, 2026Reviewed by Evan Brooks, Data Editor

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