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Federal water data

County water report

Big Horn County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Big Horn County, Wyoming.

Water grade

F

Water score

37.6

State rank

#13

of 23

Health violations

4

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

22

2,378 recent measurements

Live streamflow

50%

BIGHORN RIVER AT KANE, WY

Water at a glance

Key Water Indicators for Big Horn County

EPA SDWIS

Safety Grade

F

Score: 37.6 / 100

EPA SDWIS

Active Violations

4

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

50% of mean

BIGHORN RIVER AT KANE, WY

EPA WQP

Monitoring Sites

22

2,378 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

F

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

37.6/100

Health violations

4

Health-based violations

Violations per 100K served

38.4

Population-normalized SDWIS rate

Editorial analysis

Understanding Big Horn County’s Water

Drinking Water Quality Overview

EPA SDWIS

Big Horn County's water systems carry a failing grade, scoring 37.6 out of 100. Over the past five years, EPA SDWIS records 4 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 2026-05-14T12:15:00.000-06:00) puts BIGHORN RIVER at 1.1k cfs — well below its long-term average at 50% 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. Big Horn County has moderate coverage with 22 active monitoring sites with 2,378 recent measurements on record. Predominant monitoring categories include physical and organics, pesticide. 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 Big Horn County

Water Verdict

Big Horn County receives a poor water quality assessment with a grade of F and a score of 37.6 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

Big Horn County has recorded 4 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 38.4 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Drinking-water compliance in Big Horn County is rated Grade F, reflecting significant health-based violations in the recent reporting period. Big Horn County's drinking-water compliance score is 37.6 out of 100. The violation rate for Big Horn County is 38.4 per 100,000 people served. An NSF 53 or NSF 58-certified filter is recommended for drinking and cooking water. Check the Consumer Confidence Report from your utility to identify the specific contaminants and required corrective actions — utilities are legally required to notify customers of violations. With 22 active water-quality monitoring sites in Big Horn County, data coverage is strong. A pipeline streamflow snapshot from the BIGHORN RIVER gauge is also available on this page.

Regional Context

Big Horn County has water quality close to the average county in Wyoming. Its water score is within 1 points of the state average, meaning its overall water system performance is broadly representative of Wyoming 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 Big Horn County's water environment

Official EPA Resources for Big Horn County

EPA How's My Waterway

Interactive watershed health data for Big Horn County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Big Horn County

Consumer Confidence Reports (WY)

Annual water quality reports from utilities in Wyoming

Past 5 years

Water Quality Monitoring

Monitoring Sites

22

Active in the past 5 years

Measurements Recorded

2.4K

2,378 total readings

Most Measured

  • Physical
  • Organics, Pesticide
  • Nutrient

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

1,070cfs

May 14, 6:15 PM UTC

vs Long-Term Average

50%

Well below typical

Primary Streamgage

BIGHORN RIVER AT KANE, WY

USGS site
06279500
Drainage area
15,750 sq mi
Long-term mean
2,153 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.

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Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Big Horn County:F — Failing

High violation count or severe watershed conditions.

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 Big Horn County, Wyoming?
Big Horn County, Wyoming has a drinking-water quality grade of F with a score of 37.6/100, based on EPA SDWIS compliance data. The county has 4 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 Big Horn County?
Big Horn County has 4 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 Big Horn County?
EPA's Water Quality Portal records 2,378 measurements from 22 monitoring sites in Big Horn County over the past five years. The most frequently measured characteristic groups are Physical, Organics, Pesticide, Nutrient. 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 Big Horn County right now?
Big Horn County's primary USGS streamgage on the BIGHORN RIVER has a pipeline snapshot of 1,070 cubic feet per second — 50% of the long-term mean of 2,152.93 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 Big Horn County water compare to the Wyoming average?
Big Horn County's SDWIS water quality score of 37.6/100 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 Big Horn County?
Based on EPA SDWIS data, Big Horn County has a water quality grade of F (37.6/100). 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).
Does Big Horn County have clean drinking water?
Big Horn County has 4 health-based drinking water violations according to EPA records. With a water quality score of 37.6/100 and grade F, 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 Big Horn County rank for water quality in Wyoming?
Big Horn County ranks #13 out of 23 counties in Wyoming by SDWIS water quality score (1 = best). With a score of 37.6/100, it falls in the middle 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

Weston County

Wyoming

F

40.0

Water score

Uinta County

Wyoming

F

40.2

Water score

Sublette County

Wyoming

F

33.4

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 Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

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