waterbycounty
EPA SDWIS

Sheridan County Water Quality

Sheridan County, Wyoming

Water Grade

C

Water Score

58.4

Violations

2

State Rank

#4

of 23 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

C

Based on EPA compliance history and violation data

Water Score

58.4/100

Higher = better quality

Health Violations

2

Health-based violations

Violation Rate

7.7%

Systems with violations

Water Advisory: Sheridan County

Water Verdict

Sheridan County receives a fair water quality assessment with a grade of C and a score of 58.4 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring.

Violation Context

Sheridan County has recorded 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 7.7 violations per 1,000 residents, this rate is moderate and suggests recurring water quality challenges.

Consumer Guidance

Tap water in Sheridan County meets baseline standards, but residents who are immunocompromised or have young children may want to use an NSF-certified water filter as a precaution. With 2 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

Sheridan County has better water quality than the average county in Wyoming. Its water score is 21.8 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Past 5 years

Water Quality Monitoring

Monitoring Sites

11

Active in the past 5 years

Measurements Recorded

4.2K

4,170 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Major, Non-metals

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

91.3cfs

May 14, 6:30 PM UTC

vs Long-Term Average

34%

Well below typical

Primary Streamgage

POWDER RIVER AT ARVADA, WY

USGS site
06317000
Drainage area
5,924 sq mi
Long-term mean
269 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 Sheridan County, Wyoming?
Sheridan County, Wyoming has a drinking-water quality grade of C with a score of 58.4/100, based on EPA SDWIS compliance data. The county has 2 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 Sheridan County?
Sheridan County has 2 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 Sheridan County?
EPA's Water Quality Portal records 4,170 measurements from 11 monitoring sites in Sheridan County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Major, Non-metals. 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 Sheridan County right now?
Sheridan County's primary USGS streamgage on the POWDER RIVER is currently reading 91.3 cubic feet per second — 34% of the long-term mean of 269.1 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 Sheridan County water compare to the Wyoming average?
Sheridan County's SDWIS water quality score of 58.4/100 is higher than the Wyoming state average of 36.6. The average water quality grade across Wyoming is F, based on data from 23 counties with available SDWIS data.
Is tap water safe to drink in Sheridan County?
Based on EPA SDWIS data, Sheridan County has a water quality grade of C (58.4/100). This indicates moderate compliance. Some violations have been recorded but overall standards are maintained. 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).
Does Sheridan County have clean drinking water?
Sheridan County has 2 health-based drinking water violations according to EPA records. With a water quality score of 58.4/100 and grade C, the county's drinking water has had some compliance issues but continues to be monitored. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does Sheridan County rank for water quality in Wyoming?
Sheridan County ranks #4 out of 23 counties in Wyoming by SDWIS water quality score (1 = best). With a score of 58.4/100, 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.

Counties with Similar Water Quality

Park County

Wyoming

C

59.0

Water score

Campbell County

Wyoming

C

52.9

Water score

Albany County

Wyoming

B

66.2

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.

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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