Is Winchester, MA Tap Water Safe? Quality & Contaminants

What was found in Winchester'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
Fluoride	1100 µg/L 28% of the EPA limit 4000 µg/L Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
TTHM	43.995 µg/L 55% of the EPA limit 80 µg/L Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Chloroform	29.23 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Total Haloacetic Acids (HAA5)	11.4 µg/L 19% of the EPA limit 60 µg/L Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Bromodichloromethane	11.165 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Barium	9.55 µg/L 0.5% of the EPA limit 2000 µg/L Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Dichloroacetic Acid	7.304 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Trichloroacetic Acid	5.695 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Dibromochloromethane	4.466 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Monochloroacetic Acid	2.15 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Antimony, Total	2 µg/L 33% of the EPA limit 6 µg/L Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Bromoform	1.343 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Chromium	1.2 µg/L 1.2% of the EPA limit 100 µg/L Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Dibromoacetic Acid	1.01 µg/L No EPA limit set Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2019	1/1	SYR4
Lead	0.0042 mg/L 28% of the EPA limit 0.0150 mg/L Main supplier: WINCHESTER WATER DEPT · 22,970 people · 2023	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 Winchester

Supplier	Population served
WINCHESTER WATER DEPT	22,970

Frequently asked questions about Winchester tap water

Is Winchester tap water safe to drink?

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

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

What contaminants are in Winchester's water?

The contaminants EPA monitoring detected in Winchester include Fluoride, TTHM, Chloroform, Total Haloacetic Acids (HAA5), Bromodichloromethane. 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.