Is Holliston Water Department Tap Water Safe? Quality Report

Water source: Ground water
Ownership: Local government
Counties served: Middlesex

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

274

violations on file

still open

Violation	Type	Status	Period
MCL	Health-based	Resolved	2017-04-01 → 2017-06-30
MCL	Health-based	Resolved	2017-04-01 → 2017-06-30
MCL	Health-based	Resolved	2017-04-01 → 2017-06-30
MCL	Health-based	Resolved	2017-04-01 → 2017-06-30
MCL	Health-based	Resolved	2017-01-01 → 2017-03-31
MCL	Health-based	Resolved	2017-01-01 → 2017-03-31
MCL	Health-based	Resolved	2017-01-01 → 2017-03-31
MCL	Health-based	Resolved	2017-01-01 → 2017-03-31
MCL	Health-based	Resolved	2014-02-01 → 2014-02-28
MCL	Health-based	Resolved	2014-02-01 → 2014-02-28

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).

Contaminant	Max	Detection rate	Period
PFBS	0.0039 µg/L	4/6	2025
PFOA	0.0053 µg/L	4/6	2025
Pfhxa	0.0035 µg/L	2/6	2025
PFOS	0.0065 µg/L	2/6	2025
Pfpea	0.0033 µg/L	1/6	2025

Other contaminants detected

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 this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
TTHM	92 µg/L 115% of the EPA limit, at the 95th percentile of samples — 80 µg/L worst single sample: 110 µg/L	107/107	SYR4	2012–2019
Total Haloacetic Acids (HAA5)	48.95 µg/L 82% of the EPA limit 60 µg/L worst single sample: 93.5 µg/L	102/107	SYR4	2012–2019
Nitrate	5400 µg/L 54% of the EPA limit 10000 µg/L worst single sample: 6000 µg/L	82/94	SYR4	2012–2019
Bromodichloromethane	20.2 µg/L No EPA limit set worst single sample: 22 µg/L	77/77	SYR4	2014–2019
Chloroform	60.6 µg/L No EPA limit set worst single sample: 86 µg/L	77/77	SYR4	2014–2019
Dibromochloromethane	12 µg/L No EPA limit set worst single sample: 14 µg/L	77/77	SYR4	2014–2019
Dichloroacetic Acid	12.9 µg/L No EPA limit set worst single sample: 22 µg/L	75/77	SYR4	2014–2019
Trichloroacetic Acid	28.9 µg/L No EPA limit set worst single sample: 52 µg/L	72/77	SYR4	2014–2019
Dibromoacetic Acid	2.86 µg/L No EPA limit set worst single sample: 3.2 µg/L	65/77	SYR4	2014–2019
Bromoform	2.97 µg/L No EPA limit set worst single sample: 3.2 µg/L	63/77	SYR4	2014–2019
Monobromoacetic Acid	3.575 µg/L No EPA limit set worst single sample: 4.34 µg/L	30/77	SYR4	2014–2019
Monochloroacetic Acid	2.185 µg/L No EPA limit set worst single sample: 2.8 µg/L	24/77	SYR4	2014–2019
Lead	0.0029 mg/L 19% of the EPA limit 0.0150 mg/L	18/18	LCR	2025
Barium	41.08 µg/L 2.1% of the EPA limit 2000 µg/L worst single sample: 48.7 µg/L	13/15	SYR4	2012–2017
Fluoride	1032.5 µg/L 26% of the EPA limit 4000 µg/L worst single sample: 1100 µg/L	10/15	SYR4	2012–2017
Copper	58 µg/L 4.5% of the EPA limit 1300 µg/L worst single sample: 79 µg/L	8/8	SYR4	2015–2019
Chromium	1.38 µg/L 1.4% of the EPA limit 100 µg/L worst single sample: 1.4 µg/L	5/15	SYR4	2012–2017
2,4-D	0.7291 µg/L 1% of the EPA limit 70 µg/L worst single sample: 0.7990 µg/L	4/32	SYR4	2012–2019
Arsenic	5.27 µg/L 53% of the EPA limit 10 µg/L worst single sample: 5.3 µg/L	2/17	SYR4	2012–2017

78 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebEthylene DibromideEndrinEthylbenzeneHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPfdaPfdoaPfeesaPfhpaPfhpsPFHXSPfmbaPfmpaPFNAPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact: SEAN M REESE
Phone: 5084290603
Email: [email protected]

Frequently asked questions about Holliston Water Department

Is Holliston Water Department tap water safe to drink?

EPA monitoring detected 24 contaminants in Holliston Water Department's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Holliston Water Department's water?

EPA monitoring detected TTHM, Total Haloacetic Acids (HAA5), Nitrate, Bromodichloromethane, Chloroform, and others. The full list with the level and data source for each is above.

How many people does Holliston Water Department serve?

Holliston Water Department reports serving 15,139 people in Massachusetts, per its EPA record.

Has Holliston Water Department had any water quality violations?

The EPA has 274 violations on file for Holliston Water Department, of which 23 are health-based (a contaminant limit or required treatment was breached) and 2 remain open. The rest are monitoring or reporting failures.

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.