What was found in Meridian'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 |
|---|---|---|---|
| Nitrate | 4500 µg/L 45% of the EPA limit 10000 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019
Highest in the city: 7000 µg/L — GREENHILLS ESTATES 3 · 200 people · 2019 | 4/5 | SYR4 |
| Nitrate-Nitrite | 2840 µg/L 28% of the EPA limit 10000 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019
Highest in the city: 6900 µg/L — GREENHILLS ESTATES 3 · 200 people · 2019 | 4/5 | SYR4 |
| Fluoride | 764 µg/L 19% of the EPA limit 4000 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019
Highest in the city: 1618 µg/L — BITTERCREEK MEADOWS SUBDIVISION · 75 people · 2019 | 5/5 | SYR4 |
| Barium | 123.5 µg/L 6.2% of the EPA limit 2000 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 3/5 | SYR4 |
| Lithium | 99.5 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2025 | 1/5 | UCMR-5 |
| Copper | 84.6 µg/L 6.5% of the EPA limit 1300 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Combined Uranium | 37 µg/L 123% of the EPA limit, at the 95th percentile of samples — 30 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019
Highest in the city: 41 µg/L — GREENHILLS ESTATES 3 · 200 people · 2019 | 4/5 | SYR4 |
| Lead | 12 µg/L 80% of the EPA limit 15 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2017 | 1/5 | SYR4 |
| Gross Alpha, Excl. Radon And U | 9.28 pCi/L 62% of the EPA limit 15 pCi/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 3/5 | SYR4 |
| TTHM | 8.3 µg/L 10% of the EPA limit 80 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Total Haloacetic Acids (HAA5) | 6.15 µg/L 10% of the EPA limit 60 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Chromium | 5 µg/L 5% of the EPA limit 100 µg/L Highest in the city: GREENHILLS ESTATES 3 · 200 people · 2019 | 1/5 | SYR4 |
| Combined Radium (-226 And -228) | 4.63 pCi/L 93% of the EPA limit 5 pCi/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 3/5 | SYR4 |
| Arsenic | 4.27 µg/L 43% of the EPA limit 10 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 3/5 | SYR4 |
| Bromoform | 3.5 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 3.342 µg/L 56% of the EPA limit 6 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Dibromochloromethane | 3.22 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Xylenes, Total | 2.835 µg/L 0% of the EPA limit 10000 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Dibromoacetic Acid | 1.64 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Bromodichloromethane | 1.5 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Chloroform | 1.4 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Dichloroacetic Acid | 1.4 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Trichloroacetic Acid | 1 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Toluene | 0.7000 µg/L 0.1% of the EPA limit 1000 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Ethylbenzene | 0.5300 µg/L 0.1% of the EPA limit 700 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| Atrazine | 0.0980 µg/L 3.3% of the EPA limit 3 µg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2019 | 1/5 | SYR4 |
| PFOS | 0.0049 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2025 | 1/5 | UCMR-5 |
| Lead | 0.0039 mg/L 26% of the EPA limit 0.0150 mg/L Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2026 | 5/5 | LCR |
| PFHXS | 0.0038 µg/L No EPA limit set Main supplier: MERIDIAN WATER DEPT · 147,340 people · 2025 | 1/5 | UCMR-5 |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Meridian
| Supplier | Population served |
|---|---|
| MERIDIAN WATER DEPT | 147,340 |
| ARROWROCK RANCH | 250 |
| GREENHILLS ESTATES 3 | 200 |
| TERRACE WATER CORP INC | 84 |
| BITTERCREEK MEADOWS SUBDIVISION | 75 |
Frequently asked questions about Meridian tap water
Is Meridian tap water safe to drink?
EPA testing detected 29 contaminants in the water serving Meridian. 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 Meridian?
5 public water suppliers report drinking-water monitoring for Meridian, Idaho to the EPA. Each is listed above with its population served.
What contaminants are in Meridian's water?
The contaminants EPA monitoring detected in Meridian include Nitrate, Nitrate-Nitrite, Fluoride, Barium, Lithium. 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.