What was found in Merrillville's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Fluoride | 837 µg/L 21% of the EPA limit 4000 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2019 | 3/3 | SYR4 |
| Nitrate | 446 µg/L 4.5% of the EPA limit 10000 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2019 | 1/3 | SYR4 |
| Nitrate-Nitrite | 395.5 µg/L 4% of the EPA limit 10000 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2019 | 1/3 | SYR4 |
| Copper | 375.8 µg/L 29% of the EPA limit 1300 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2018 | 3/3 | SYR4 |
| Barium | 219 µg/L 11% of the EPA limit 2000 µg/L Highest in the city: CROSSINGS MOBILE HOME PARK · 100 people · 2018 | 2/3 | SYR4 |
| TTHM | 33.395 µg/L 42% of the EPA limit 80 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2019 | 1/3 | SYR4 |
| Lead | 12.9 µg/L 86% of the EPA limit 15 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2018
Highest in the city: 29.8 µg/L — CROSSINGS MOBILE HOME PARK · 100 people · 2019 | 3/3 | SYR4 |
| Chromium | 22.255 µg/L 22% of the EPA limit 100 µg/L Highest in the city: ROCKWELL SHORES APARTMENTS · 45 people · 2018 | 2/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 20.475 µg/L 34% of the EPA limit 60 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2019 | 1/3 | SYR4 |
| Gross Alpha, Excl. Radon And U | 0.2330 pCi/L 1.6% of the EPA limit 15 pCi/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2015
Highest in the city: 8.7 pCi/L — CROSSINGS MOBILE HOME PARK · 100 people · 2018 | 3/3 | SYR4 |
| Arsenic | 6.6 µg/L 66% of the EPA limit 10 µg/L Highest in the city: ROCKWELL SHORES APARTMENTS · 45 people · 2018 | 1/3 | SYR4 |
| Cyanide | 6 µg/L 3% of the EPA limit 200 µg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2019 | 1/3 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 3.3 µg/L 55% of the EPA limit 6 µg/L Highest in the city: ROCKWELL SHORES APARTMENTS · 45 people · 2019 | 1/3 | SYR4 |
| Lead | 0.0030 mg/L 20% of the EPA limit 0.0150 mg/L Main supplier: INDIANA AMERICAN WATER - NORTHWEST · 210,510 people · 2024
Highest in the city: 0.0046 mg/L — CROSSINGS MOBILE HOME PARK · 100 people · 2025 | 3/3 | LCR |
Water suppliers serving Merrillville
| Supplier | Population served |
|---|---|
| INDIANA AMERICAN WATER - NORTHWEST | 210,510 |
| CROSSINGS MOBILE HOME PARK | 100 |
| ROCKWELL SHORES APARTMENTS | 45 |
Frequently asked questions about Merrillville tap water
Is Merrillville tap water safe to drink?
EPA testing detected 14 contaminants in the water serving Merrillville. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Merrillville?
3 public water suppliers report drinking-water monitoring for Merrillville, Indiana to the EPA. Each is listed above with its population served.
What contaminants are in Merrillville's water?
The contaminants EPA monitoring detected in Merrillville include Fluoride, Nitrate, Nitrate-Nitrite, Copper, Barium. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.