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EPA SDWIS

Sanilac County Water Quality

Sanilac County, Michigan

Water Grade

C

Water Score

55.4

Violations

2

State Rank

#49

of 83 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

C

Based on EPA compliance history and violation data

Water Score

55.4/100

Higher = better quality

Health Violations

2

Health-based violations

Violation Rate

10.1%

Systems with violations

Water Advisory: Sanilac County

Water Verdict

Sanilac County receives a fair water quality assessment with a grade of C and a score of 55.4 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

Sanilac County has recorded 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 10.1 violations per 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Tap water in Sanilac 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

Sanilac County has water quality close to the average county in Michigan. Its water score is within 3.1 points of the state average, meaning its overall water system performance is broadly representative of Michigan as a whole.

Past 5 years

Water Quality Monitoring

Monitoring Sites

47

Active in the past 5 years

Measurements Recorded

5.8K

5,841 total readings

Most Measured

  • Physical
  • Microbiological
  • Organics, Other

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).

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Frequently Asked Questions

What is the water quality in Sanilac County, Michigan?
Sanilac County, Michigan has a drinking-water quality grade of C with a score of 55.4/100, 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 Sanilac County?
Sanilac 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 Sanilac County?
EPA's Water Quality Portal records 5,841 measurements from 47 monitoring sites in Sanilac County over the past five years. The most frequently measured characteristic groups are Physical, Microbiological, Organics, Other. 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.
How does Sanilac County water compare to the Michigan average?
Sanilac County's SDWIS water quality score of 55.4/100 is lower than the Michigan state average of 58.5. The average water quality grade across Michigan is D, based on data from 83 counties with available SDWIS data.
Is tap water safe to drink in Sanilac County?
Based on EPA SDWIS data, Sanilac County has a water quality grade of C (55.4/100). 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 Sanilac County have clean drinking water?
Sanilac County has 2 health-based drinking water violations according to EPA records. With a water quality score of 55.4/100 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 Sanilac County rank for water quality in Michigan?
Sanilac County ranks #49 out of 83 counties in Michigan by SDWIS water quality score (1 = best). With a score of 55.4/100, 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

Montcalm County

Michigan

C

54.8

Water score

Eaton County

Michigan

C

56.3

Water score

St. Joseph County

Michigan

C

56.3

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.

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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