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Tap water quality report

Holliston, MA

EPA monitoring detected 24 contaminants across the 1 water supplier serving Holliston. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

1
water supplier
15,139
people served
24
contaminants found
Massachusetts rankings Lead in Massachusetts PFAS in Massachusetts

What was found in Holliston'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.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
5400 µg/L 54%
of the EPA limit 10000 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Fluoride
1032.5 µg/L 26%
of the EPA limit 4000 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2017
1/1 SYR4
TTHM
92 µg/L 115%
of the EPA limit, at the 95th percentile of samples — 80 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Chloroform
60.6 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Copper
58 µg/L 4.5%
of the EPA limit 1300 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
48.95 µg/L 82%
of the EPA limit 60 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Barium
41.08 µg/L 2.1%
of the EPA limit 2000 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2017
1/1 SYR4
Trichloroacetic Acid
28.9 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Bromodichloromethane
20.2 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Dichloroacetic Acid
12.9 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Dibromochloromethane
12 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Arsenic
5.27 µg/L 53%
of the EPA limit 10 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2017
1/1 SYR4
Monobromoacetic Acid
3.575 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Bromoform
2.97 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Dibromoacetic Acid
2.86 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Monochloroacetic Acid
2.185 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
Chromium
1.38 µg/L 1.4%
of the EPA limit 100 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2017
1/1 SYR4
2,4-D
0.7291 µg/L 1%
of the EPA limit 70 µg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2019
1/1 SYR4
PFOS
0.0065 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2025
1/1 UCMR-5
PFOA
0.0053 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2025
1/1 UCMR-5
PFBS
0.0039 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2025
1/1 UCMR-5
Pfhxa
0.0035 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2025
1/1 UCMR-5
Pfpea
0.0033 µg/L
No EPA limit set
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 people · 2025
1/1 UCMR-5
Lead
0.0029 mg/L 19%
of the EPA limit 0.0150 mg/L
Main supplier: HOLLISTON WATER DEPARTMENT · 15,139 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 Holliston

SupplierPopulation served
HOLLISTON WATER DEPARTMENT 15,139

Frequently asked questions about Holliston tap water

Is Holliston tap water safe to drink?

EPA testing detected 24 contaminants in the water serving Holliston. 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 Holliston?

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

What contaminants are in Holliston's water?

The contaminants EPA monitoring detected in Holliston include Nitrate, Fluoride, TTHM, Chloroform, Copper. 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.