Is Yarmouth, MA Tap Water Safe? Quality & Contaminants

What was found in Yarmouth'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	5700 µg/L 57% of the EPA limit 10000 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2019	1/1	SYR4
Copper	740.4999999999998 µg/L 57% of the EPA limit 1300 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2016	1/1	SYR4
Barium	75.19999999999982 µg/L 3.8% of the EPA limit 2000 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2018	1/1	SYR4
Tetrachloroethylene	8.86 µg/L 177% of the EPA limit, at the 95th percentile of samples — 5 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2019	1/1	SYR4
Lead	8.275 µg/L 55% of the EPA limit 15 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2016	1/1	SYR4
Cadmium	1.3 µg/L 26% of the EPA limit 5 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2018	1/1	SYR4
cis-1,2-Dichloroethylene	1.18 µg/L 1.7% of the EPA limit 70 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2019	1/1	SYR4
Pfpea	0.0594 µg/L No EPA limit set Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2025	1/1	UCMR-5
Heptachlor Epoxide	0.0410 µg/L 21% of the EPA limit 0.2000 µg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2018	1/1	SYR4
Pfhxa	0.0406 µg/L No EPA limit set Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2025	1/1	UCMR-5
Pfba	0.0127 µg/L No EPA limit set Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2025	1/1	UCMR-5
Pfhpa	0.0077 µg/L No EPA limit set Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2025	1/1	UCMR-5
PFHXS	0.0031 µg/L No EPA limit set Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 people · 2025	1/1	UCMR-5
Lead	0.0015 mg/L 10% of the EPA limit 0.0150 mg/L Main supplier: YARMOUTH WATER DEPARTMENT · 38,900 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 Yarmouth

Supplier	Population served
YARMOUTH WATER DEPARTMENT	38,900

Frequently asked questions about Yarmouth tap water

Is Yarmouth tap water safe to drink?

EPA testing detected 14 contaminants in the water serving Yarmouth. 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 Yarmouth?

1 public water supplier report drinking-water monitoring for Yarmouth, Massachusetts to the EPA. Each is listed above with its population served.

What contaminants are in Yarmouth's water?

The contaminants EPA monitoring detected in Yarmouth include Nitrate, Copper, Barium, Tetrachloroethylene, Lead. 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.