waterbycounty
EPA SDWIS

Dearborn County Water Quality

Dearborn County, Indiana

Water Grade

C

Water Score

57.5

Violations

4

State Rank

#37

of 92 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

C

Based on EPA compliance history and violation data

Water Score

57.5/100

Higher = better quality

Health Violations

4

Health-based violations

Violation Rate

8.5%

Systems with violations

Water Advisory: Dearborn County

Water Verdict

Dearborn County receives a fair water quality assessment with a grade of C and a score of 57.5 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

Dearborn County has recorded 4 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 8.5 violations per 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Tap water in Dearborn 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 4 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

Dearborn County has better water quality than the average county in Indiana. Its water score is 5 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

27.5%

44 of 160 assessed

Some impairment

Top Impairment Causes

  • 1

    ESCHERICHIA COLI (E. COLI)

  • 2

    BIOLOGICAL INTEGRITY

  • 3

    PCBS IN FISH TISSUE

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

10

Active in the past 5 years

Measurements Recorded

4.3K

4,320 total readings

Most Measured

  • Physical
  • Inorganics, Minor, Metals
  • 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).

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Frequently Asked Questions

What is the water quality in Dearborn County, Indiana?
Dearborn County, Indiana has a drinking-water quality grade of C with a score of 57.5/100, 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 live streamflow are reported separately on this page.
Are there any water violations in Dearborn County?
Dearborn 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 healthy are the watersheds in Dearborn County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 27.5% of Dearborn County's 160 assessed water bodies are classified as impaired (44 impaired). The top reported causes are ESCHERICHIA COLI (E. COLI), BIOLOGICAL INTEGRITY, PCBS IN FISH TISSUE. 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 Dearborn County?
EPA's Water Quality Portal records 4,320 measurements from 10 monitoring sites in Dearborn County over the past five years. The most frequently measured characteristic groups are Physical, Inorganics, Minor, Metals, 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.
How does Dearborn County water compare to the Indiana average?
Dearborn County's SDWIS water quality score of 57.5/100 is higher than the Indiana state average of 52.5. The average water quality grade across Indiana is D, based on data from 92 counties with available SDWIS data.
Is tap water safe to drink in Dearborn County?
Based on EPA SDWIS data, Dearborn County has a water quality grade of C (57.5/100). 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 Dearborn County have clean drinking water?
Dearborn County has 4 health-based drinking water violations according to EPA records. With a water quality score of 57.5/100 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 Dearborn County rank for water quality in Indiana?
Dearborn County ranks #37 out of 92 counties in Indiana by SDWIS water quality score (1 = best). With a score of 57.5/100, 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

Marshall County

Indiana

C

57.1

Water score

Grant County

Indiana

C

56.8

Water score

Putnam County

Indiana

C

58.3

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.

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.

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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