Is Barnstable, MA Tap Water Safe? Quality & Contaminants

What was found in Barnstable's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

Contaminant	Level vs EPA limit	Suppliers	Source
Nitrate	6000 µg/L 60% of the EPA limit 10000 µg/L	4/4	SYR4
Copper	604 µg/L 46% of the EPA limit 1300 µg/L	4/4	SYR4
Nitrite	440 µg/L 44% of the EPA limit 1000 µg/L	1/4	SYR4
Barium	123 µg/L 6.2% of the EPA limit 2000 µg/L	4/4	SYR4
Fluoride	100 µg/L 2.5% of the EPA limit 4000 µg/L	2/4	SYR4
TTHM	23.6 µg/L 30% of the EPA limit 80 µg/L	3/4	SYR4
Total Haloacetic Acids (HAA5)	10.3 µg/L 17% of the EPA limit 60 µg/L	3/4	SYR4
Dibromochloromethane	9.1 µg/L No EPA limit set	3/4	SYR4
Bromodichloromethane	8.3 µg/L No EPA limit set	3/4	SYR4
Bromoform	6.3 µg/L No EPA limit set	3/4	SYR4
Chloroform	4.5 µg/L No EPA limit set	3/4	SYR4
Monochloroacetic Acid	4.3 µg/L No EPA limit set	2/4	SYR4
Arsenic	4 µg/L 40% of the EPA limit 10 µg/L	1/4	SYR4
Selenium	4 µg/L 8% of the EPA limit 50 µg/L	1/4	SYR4
Monobromoacetic Acid	3.9 µg/L No EPA limit set	3/4	SYR4
Dibromoacetic Acid	3.5 µg/L No EPA limit set	3/4	SYR4
Tetrachloroethylene	2.8 µg/L 56% of the EPA limit 5 µg/L	1/4	SYR4
Dichloroacetic Acid	2.2 µg/L No EPA limit set	2/4	SYR4
Trichloroacetic Acid	2.1 µg/L No EPA limit set	3/4	SYR4
cis-1,2-Dichloroethylene	2 µg/L 2.9% of the EPA limit 70 µg/L	1/4	SYR4
Trichloroethylene	0.6500 µg/L 13% of the EPA limit 5 µg/L	1/4	SYR4
Cadmium	0.2100 µg/L 4.2% of the EPA limit 5 µg/L	1/4	SYR4
Pfpea	0.0298 µg/L No EPA limit set	3/4	UCMR-5
PFBS	0.0182 µg/L No EPA limit set	2/4	UCMR-5
Pfba	0.0168 µg/L No EPA limit set	1/4	UCMR-5
PFOS	0.0071 µg/L No EPA limit set	1/4	UCMR-5
Pfhxa	0.0069 µg/L No EPA limit set	3/4	UCMR-5
PFOA	0.0049 µg/L No EPA limit set	2/4	UCMR-5
PFHXS	0.0036 µg/L No EPA limit set	2/4	UCMR-5
Lead	0.0031 mg/L 21% of the EPA limit 0.0150 mg/L	4/4	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 single worst sample on record — 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 Barnstable

Supplier	Population served
CENTERVILLE OSTERVILLE MARSTONS MILLS WD	50,000
HYANNIS WATER SYSTEM, TOWN OF BARNSTABLE	35,000
BARNSTABLE FIRE DISTRICT	5,400
COTUIT FIRE DISTRICT WATER DEPARTMENT	4,938

Frequently asked questions about Barnstable tap water

Is Barnstable tap water safe to drink?

EPA testing detected 30 contaminants in the water serving Barnstable. 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 Barnstable?

4 public water suppliers report drinking-water monitoring for Barnstable, Massachusetts to the EPA. Each is listed above with its population served.

What contaminants are in Barnstable's water?

The contaminants EPA monitoring detected in Barnstable include Nitrate, Copper, Nitrite, Barium, Fluoride. The full list, with the highest level found 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.