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County water report

Sweetwater County Water Report

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

Water grade

D

Water score

43.8

State rank

#9

of 23

Health violations

12

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

1 water bodies assessed

Monitoring sites

18

9,706 recent measurements

Live streamflow

55%

GREEN RIVER NEAR GREEN RIVER, WY

Water at a glance

Key Water Indicators for Sweetwater County

EPA SDWIS

Safety Grade

D

Score: 43.8 / 100

EPA SDWIS

Active Violations

12

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

1 bodies assessed

USGS NWIS

Streamflow Snapshot

55% of mean

GREEN RIVER NEAR GREEN RIVER, WY

EPA WQP

Monitoring Sites

18

9,706 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

D

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

43.8/100

Health violations

12

Health-based violations

Violations per 100K served

25.6

Population-normalized SDWIS rate

Editorial analysis

Understanding Sweetwater County’s Water

Drinking Water Quality Overview

EPA SDWIS

Sweetwater County's drinking water received a D grade, scoring 43.8 out of 100. Over the past five years, EPA SDWIS records 12 health-based violations — a pattern that public water utilities are required to disclose and correct.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). None of the assessed waterways are listed as impaired (0 of 1 water bodies) across Sweetwater County's watersheds. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T12:30:00.000-06:00) puts GREEN RIVER at 877.0 cfs — well below its long-term average at 55% 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. Sweetwater County has moderate coverage with 18 active monitoring sites with 9,706 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 Sweetwater County

Water Verdict

Sweetwater County, Wyoming receives a below-average water quality assessment with a grade of D and a score of 43.8 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking. Separately, EPA ATTAINS assessments track 1 water body in the county's watershed, none of which are currently listed as impaired under the Clean Water Act. At the most recent USGS reading, local streamflow was below its historical mean at 55.4% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Sweetwater County, Wyoming show 12 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 25.6 violations per 100,000 people served, this rate is high and signals significant water quality management issues. For independent context, 9,706 water-quality monitoring results have been recorded across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Sweetwater County's drinking-water compliance is below average with a Grade D, indicating repeated or unresolved violations in the recent record. Sweetwater County's drinking-water compliance score is 43.8 out of 100. The violation rate for Sweetwater County is 25.6 per 100,000 people served. Residents are encouraged to use an NSF 53 or NSF 58-certified filter for drinking and cooking water until the underlying violations are resolved. Running tap water for 30 seconds before use and avoiding older lead-pipe connections can also reduce exposure risk. The current Consumer Confidence Report from your utility will specify the contaminants of concern. With 18 active water-quality monitoring sites in Sweetwater County, data coverage is strong. A pipeline streamflow snapshot from the GREEN RIVER gauge is also available on this page.

Regional Context

Sweetwater County has better water quality than the average county in Wyoming. Its water score is 7.2 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

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 Sweetwater County's water environment

Official EPA Resources for Sweetwater County

EPA How's My Waterway

Interactive watershed health data for Sweetwater County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Sweetwater County

Consumer Confidence Reports (WY)

Annual water quality reports from utilities in Wyoming

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

0.0%

0 of 1 assessed

Mostly healthy

Top Impairment Causes

No specific impairment causes reported for the assessed water bodies in this county.

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

18

Active in the past 5 years

Measurements Recorded

9.7K

9,706 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Minor, 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

877cfs

May 14, 6:30 PM UTC

vs Long-Term Average

55%

Well below typical

Primary Streamgage

GREEN RIVER NEAR GREEN RIVER, WY

USGS site
09217000
Drainage area
14,000 sq mi
Long-term mean
1,582 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

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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 Sweetwater County: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 Sweetwater County, Wyoming?
Sweetwater County, Wyoming has a drinking-water quality grade of D with a score of 43.8/100, based on EPA SDWIS compliance data. The county has 12 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 Sweetwater County?
Sweetwater County has 12 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 Sweetwater County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of Sweetwater County's 1 assessed water bodies are classified as impaired (0 impaired). 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 Sweetwater County?
EPA's Water Quality Portal records 9,706 measurements from 18 monitoring sites in Sweetwater County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Minor, 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 Sweetwater County right now?
Sweetwater County's primary USGS streamgage on the GREEN RIVER has a pipeline snapshot of 877 cubic feet per second — 55% of the long-term mean of 1,581.96 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 Sweetwater County water compare to the Wyoming average?
Sweetwater County's SDWIS water quality score of 43.8/100 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 Sweetwater County?
Based on EPA SDWIS data, Sweetwater County has a water quality grade of D (43.8/100). 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 Sweetwater County have so many water violations?
Sweetwater County has 12 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 Sweetwater County rank for water quality in Wyoming?
Sweetwater County ranks #9 out of 23 counties in Wyoming by SDWIS water quality score (1 = best). With a score of 43.8/100, 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

Natrona County

Wyoming

D

43.6

Water score

Hot Springs County

Wyoming

D

44.6

Water score

Laramie County

Wyoming

D

46.7

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

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