Water quality · Indiana
Water quality in Indiana
2 of the 4 Indiana ZIPs matched to an EPA SDWIS community water system report a health-based violation in the last 3 years. SDWIS reports the system serving the county, never an address-level test, and never private wells.
Last verified 2026-09-24 · methodology
Water quality by ZIP code in Indiana
The largest community water system EPA lists for each ZIP's county, and its health-based violations in the last 3 years.
| ZIP | Largest system | Health-based violations |
|---|---|---|
| 46204IndianapolisMarion County | CITIZENS WATER - INDIANAPOLIS | None |
| 47401Bloomington (IN)Monroe County | CITY OF BLOOMINGTON UTILITIES | 1 |
| 47906West Lafayette (IN)Tippecanoe County | LAFAYETTE WATER WORKS | None |
| 46032Carmel (IN)Hamilton County | CARMEL WATER DEPARTMENT | 1 |
County-level figures from EPA SDWIS, joined to each ZIP by county. None of them is a measurement at a specific address.
What lands here
Pages show the largest community water system on record for the ZIP's county, its PWSID and population served, and its health-based and total violations in the last 3 years. Lead and copper sampling results are not shown; your utility's annual water quality report (CCR) has them.
Source & refresh
EPA SDWIS. Refreshed quarterly (federal mandate). Primary source →
Indiana top concern
Radon, lead pipes (older Rust Belt cities)
Indiana has Zone 1 radon coverage across most counties. Lead-service-line inventories under LCRR are heaviest in Gary, South Bend, Hammond, Indianapolis. Tornado exposure peaks April-June.
See Indiana state page for the full state-level rollup across all 12 dimensions.
Read more on water quality
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EPA Radon Zones — what 1, 2, and 3 mean and when you should test
EPA classifies every US county into Zone 1 (high), Zone 2 (moderate), or Zone 3 (low) for radon. Plain-English guide to the classifications and at-home testing.
EPA AQI categories explained — what 0–50 Good through 301–500 Hazardous mean
Plain-English guide to the six EPA Air Quality Index categories: 0–50 Good, 51–100 Moderate, 101–150 Unhealthy for Sensitive Groups, 151–200 Unhealthy, 201–300 Very Unhealthy, 301–500 Hazardous — what each level means and who is at risk.
Lead and Copper Rule 2024 — the federal lead-pipe inventory mandate
The 2024 Lead and Copper Rule Revisions (LCRR) require every US community water system to inventory and report lead service lines. Plain-English guide.