Is St. John, ND Tap Water Safe? Quality & Contaminants

What was found in St. John'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-Nitrite	540 µg/L 5.4% of the EPA limit 10000 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2019	1/1	SYR4
Copper	459.9 µg/L 35% of the EPA limit 1300 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2019	1/1	SYR4
Fluoride	267 µg/L 6.7% of the EPA limit 4000 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Chromium	19.7 µg/L 20% of the EPA limit 100 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Gross Alpha, Excl. Radon And U	16.866 pCi/L 112% of the EPA limit, at the 95th percentile of samples — 15 pCi/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Lead	16.22 µg/L 108% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2019	1/1	SYR4
Combined Uranium	12.63 µg/L 42% of the EPA limit 30 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Barium	1.98 µg/L 0.1% of the EPA limit 2000 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Selenium	1.23 µg/L 2.5% of the EPA limit 50 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Dibromoacetic Acid	1.04 µg/L No EPA limit set Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Total Haloacetic Acids (HAA5)	1.04 µg/L 1.7% of the EPA limit 60 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Combined Radium (-226 And -228)	0.8340 pCi/L 17% of the EPA limit 5 pCi/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
TTHM	0.5780 µg/L 0.7% of the EPA limit 80 µg/L Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Chloroform	0.5400 µg/L No EPA limit set Main supplier: ST JOHN CITY OF · 341 people · 2017	1/1	SYR4
Lead	0.0024 mg/L 16% of the EPA limit 0.0150 mg/L Main supplier: ST JOHN CITY OF · 341 people · 2025	1/1	LCR

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 St. John

Supplier	Population served
ST JOHN CITY OF	341

Frequently asked questions about St. John tap water

Is St. John tap water safe to drink?

EPA testing detected 15 contaminants in the water serving St. John. 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 St. John?

1 public water supplier report drinking-water monitoring for St. John, North Dakota to the EPA. Each is listed above with its population served.

What contaminants are in St. John's water?

The contaminants EPA monitoring detected in St. John include Nitrate-Nitrite, Copper, Fluoride, Chromium, Gross Alpha, Excl. Radon And U. 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.