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EPA SDWIS

Trempealeau County Water Quality

Trempealeau County, Wisconsin

Water Grade

F

Water Score

29.1

Violations

12

State Rank

#50

of 71 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

F

Based on EPA compliance history and violation data

Water Score

29.1/100

Higher = better quality

Health Violations

12

Health-based violations

Violation Rate

71.3%

Systems with violations

Water Advisory: Trempealeau County

Water Verdict

Trempealeau County receives a poor water quality assessment with a grade of F and a score of 29.1 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

Trempealeau County has recorded 12 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 71.3 violations per 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Residents of Trempealeau 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 12 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

Trempealeau County has poorer water quality than the average county in Wisconsin. Its water score is 10.4 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

12.5%

42 of 337 assessed

Some impairment

Top Impairment Causes

  • 1

    PHOSPHORUS, TOTAL

  • 2

    TOTAL SUSPENDED SOLIDS (TSS)

  • 3

    MERCURY

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

78

Active in the past 5 years

Measurements Recorded

9.4K

9,431 total readings

Most Measured

  • Organics, Pesticide
  • Physical
  • 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

591cfs

May 14, 6:00 PM UTC

vs Long-Term Average

121%

Above typical

Primary Streamgage

TREMPEALEAU RIVER AT DODGE, WI

USGS site
05379500
Drainage area
643 sq mi
Long-term mean
487 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 Trempealeau County, Wisconsin?
Trempealeau County, Wisconsin has a drinking-water quality grade of F with a score of 29.1/100, 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 live streamflow are reported separately on this page.
Are there any water violations in Trempealeau County?
Trempealeau 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 Trempealeau County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 12.5% of Trempealeau County's 337 assessed water bodies are classified as impaired (42 impaired). The top reported causes are PHOSPHORUS, TOTAL, TOTAL SUSPENDED SOLIDS (TSS), MERCURY. 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 Trempealeau County?
EPA's Water Quality Portal records 9,431 measurements from 78 monitoring sites in Trempealeau County over the past five years. The most frequently measured characteristic groups are Organics, Pesticide, Physical, 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 Trempealeau County right now?
Trempealeau County's primary USGS streamgage on the TREMPEALEAU RIVER is currently reading 591 cubic feet per second — 121% of the long-term mean of 486.75 cfs. Flow is within typical range for this gauge. For genuine real-time data, visit waterdata.usgs.gov.
How does Trempealeau County water compare to the Wisconsin average?
Trempealeau County's SDWIS water quality score of 29.1/100 is lower than the Wisconsin state average of 39.5. The average water quality grade across Wisconsin is F, based on data from 71 counties with available SDWIS data.
Is tap water safe to drink in Trempealeau County?
Based on EPA SDWIS data, Trempealeau County has a water quality grade of F (29.1/100). 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 Trempealeau County have so many water violations?
Trempealeau 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 Trempealeau County rank for water quality in Wisconsin?
Trempealeau County ranks #50 out of 71 counties in Wisconsin by SDWIS water quality score (1 = best). With a score of 29.1/100, 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

Jefferson County

Wisconsin

F

28.7

Water score

Jackson County

Wisconsin

F

30.3

Water score

Grant County

Wisconsin

F

27.9

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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