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EPA SDWIS

Clarke County Water Quality

Clarke County, Virginia

Water Grade

F

Water Score

5.8

Violations

40

State Rank

#91

of 95 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

F

Based on EPA compliance history and violation data

Water Score

5.8/100

Higher = better quality

Health Violations

40

Health-based violations

Violation Rate

631.5%

Systems with violations

Water Advisory: Clarke County

Water Verdict

Clarke County receives a poor water quality assessment with a grade of F and a score of 5.8 out of 100. The water supply has documented quality issues. Residents are strongly encouraged to use filtered or bottled water for drinking and to stay informed about utility improvement plans.

Violation Context

Clarke County has recorded 40 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 631.5 violations per 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Residents of Clarke County are advised to use filtered or bottled water for drinking and cooking until water quality improves. A reverse-osmosis or activated-carbon filter certified to remove the contaminants listed in the utility's Consumer Confidence Report is recommended. With 40 recorded health violations, staying informed about utility communications and boil-water notices is especially important. For long-term peace of mind, request your utility's latest Consumer Confidence Report and consider independent water testing if you have specific health concerns.

Regional Context

Clarke County has poorer water quality than the average county in Virginia. Its water score is 51.9 points lower than the state average, suggesting more challenges with contamination control or infrastructure than neighboring counties.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

45.5%

20 of 44 assessed

Moderate concern

Top Impairment Causes

  • 1

    ESCHERICHIA COLI (E. COLI)

  • 2

    PCBS IN FISH TISSUE

  • 3

    MERCURY IN FISH TISSUE

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state — counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

14

Active in the past 5 years

Measurements Recorded

2.0K

1,974 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

10.1cfs

May 14, 6:45 PM UTC

vs Long-Term Average

50%

Well below typical

Primary Streamgage

SPOUT RUN AT RT 621 NEAR MILLWOOD, VA

USGS site
01636316
Drainage area
21.4 sq mi
Long-term mean
20.4 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; "% of typical" compares the latest reading against that average.

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Frequently Asked Questions

What is the water quality in Clarke County, Virginia?
Clarke County, Virginia has a drinking-water quality grade of F with a score of 5.8/100, based on EPA SDWIS compliance data. The county has 40 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and live streamflow are reported separately on this page.
Are there any water violations in Clarke County?
Clarke County has 40 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 healthy are the watersheds in Clarke County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 45.5% of Clarke County's 44 assessed water bodies are classified as impaired (20 impaired). The top reported causes are ESCHERICHIA COLI (E. COLI), PCBS IN FISH TISSUE, MERCURY IN FISH TISSUE. Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How much water-quality monitoring happens in Clarke County?
EPA's Water Quality Portal records 1,974 measurements from 14 monitoring sites in Clarke County 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 Clarke County right now?
Clarke County's primary USGS streamgage on the SPOUT RUN is currently reading 10.1 cubic feet per second — 50% of the long-term mean of 20.41 cfs. This is well below typical — often a signal of drought stress on source water. For genuine real-time data, visit waterdata.usgs.gov.
How does Clarke County water compare to the Virginia average?
Clarke County's SDWIS water quality score of 5.8/100 is lower than the Virginia state average of 57.7. The average water quality grade across Virginia is D, based on data from 95 counties with available SDWIS data.
Is tap water safe to drink in Clarke County?
Based on EPA SDWIS data, Clarke County has a water quality grade of F (5.8/100). This indicates below-average compliance with significant violations. Residents may want to consider home water filtration or independent testing. 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 Clarke County have so many water violations?
Clarke County has 40 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 Clarke County rank for water quality in Virginia?
Clarke County ranks #91 out of 95 counties in Virginia by SDWIS water quality score (1 = best). With a score of 5.8/100, it falls in the bottom 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.

Counties with Similar Water Quality

Brunswick County

Virginia

F

3.8

Water score

Madison County

Virginia

F

7.9

Water score

Isle of Wight County

Virginia

F

3.0

Water score

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.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments — state-reported, EPA-finalized.

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 Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

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