Tap Water Quality Report
Tap water quality in GARY, Indiana
Tap water in GARY, Indiana receives a grade of B (87/100) from TapWaterSafety.org. It's served by INDIANA AMERICAN WATER - NORTHWEST. The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in GARY's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving GARY.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 19.0 ppb, 316x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 23.7 ppb, 158x above the EWG health guideline of 0.15 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 11.8 ppb, 118x above the EWG health guideline of 0.1 ppb.
EPA compliance record
Official U.S. EPA records for INDIANA AMERICAN WATER - NORTHWEST (system ID IN5245015) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for GARY
Filters matched to the specific contaminants in GARY's water supply.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in GARY's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
19.0 ppb | 0.06 | — | — | — | — | — | 316× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
23.7 ppb | 0.15 | 80.0 | 100 | — | — | — | 158× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
11.8 ppb | 0.1 | 60.0 | 60 | — | — | — | 118× over |
| Chromium (hexavalent) Heavy metal |
0.303 ppb | 0.02 | — | — | — | — | — | 15× over |
| Nitrate Inorganic |
0.853 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 6.1× over |
| Nitrate and nitrite Inorganic |
0.345 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.5× over |
| 1,4-Dioxane Semi-volatile organic compound |
0.0588 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Molybdenum Other |
1.36 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.114 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.37 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Testosterone Other |
0.018 ppt | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from INDIANA AMERICAN WATER - NORTHWEST.