Is Monmouth, ME Tap Water Safe? Quality & Contaminants

What was found in Monmouth'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	980 µg/L 9.8% of the EPA limit 10000 µg/L Highest in the city: BLUE ROCK COOPERATIVE · 105 people · 2019	1/2	SYR4
Nitrate-Nitrite	927 µg/L 9.3% of the EPA limit 10000 µg/L Highest in the city: BLUE ROCK COOPERATIVE · 105 people · 2018	1/2	SYR4
Copper	149.4 µg/L 11% of the EPA limit 1300 µg/L Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2019	2/2	SYR4
Fluoride	100 µg/L 2.5% of the EPA limit 4000 µg/L Highest in the city: BLUE ROCK COOPERATIVE · 105 people · 2018	1/2	SYR4
TTHM	41.5 µg/L 52% of the EPA limit 80 µg/L Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2019	1/2	SYR4
Total Haloacetic Acids (HAA5)	38.8 µg/L 65% of the EPA limit 60 µg/L Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2019	1/2	SYR4
Chloroform	33.9 µg/L No EPA limit set Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2013	1/2	SYR4
Lead	18.925 µg/L 126% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2019	2/2	SYR4
Trichloroacetic Acid	12 µg/L No EPA limit set Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2013	1/2	SYR4
Arsenic	9.28 µg/L 93% of the EPA limit 10 µg/L Highest in the city: BLUE ROCK COOPERATIVE · 105 people · 2019	1/2	SYR4
Chromium	5.39 µg/L 5.4% of the EPA limit 100 µg/L Highest in the city: BLUE ROCK COOPERATIVE · 105 people · 2018	1/2	SYR4
Barium	5.27 µg/L 0.3% of the EPA limit 2000 µg/L Highest in the city: BLUE ROCK COOPERATIVE · 105 people · 2018	1/2	SYR4
Bromodichloromethane	3.495 µg/L No EPA limit set Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2013	1/2	SYR4
Combined Radium (-226 And -228)	0.7720 pCi/L 15% of the EPA limit 5 pCi/L Highest in the city: BLUE ROCK COOPERATIVE · 105 people · 2015	1/2	SYR4
Lead	0.0015 mg/L 10% of the EPA limit 0.0150 mg/L Main supplier: MONMOUTH WATER ASSOCIATION · 588 people · 2025	2/2	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 Monmouth

Supplier	Population served
MONMOUTH WATER ASSOCIATION	588
BLUE ROCK COOPERATIVE	105

Frequently asked questions about Monmouth tap water

Is Monmouth tap water safe to drink?

EPA testing detected 15 contaminants in the water serving Monmouth. 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 Monmouth?

2 public water suppliers report drinking-water monitoring for Monmouth, Maine to the EPA. Each is listed above with its population served.

What contaminants are in Monmouth's water?

The contaminants EPA monitoring detected in Monmouth include Nitrate, Nitrate-Nitrite, Copper, Fluoride, TTHM. 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.