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Tap water quality report

Cohasset Water Dept

EPA monitoring tested this supplier for 105 contaminants and detected 24. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

105
contaminants tested
24
detected
7,555
people served
3
health-based violations
Massachusetts rankingsLead in MassachusettsPFAS in Massachusetts
Water source
Surface water
Ownership
Local government
Counties served
Norfolk

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.

3
health-based violations
59
violations on file
0
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 2008-04-01
TT Health-based Resolved 2008-04-01
MCL Health-based Archived 1996-08-01 → 1996-08-31
Other Monitoring Resolved 2022-07-01
Other Monitoring Resolved 2022-07-01
MR Monitoring Archived 2021-06-01 → 2021-06-30
MR Monitoring Archived 2021-04-01 → 2021-06-30
MR Monitoring Archived 2021-04-01 → 2021-06-30
MR Monitoring Archived 2021-04-01 → 2021-06-30
MR Monitoring Archived 2021-04-01 → 2021-06-30

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
PFOA 0.0067 µg/L 2/3 2025
Pfba 0.0073 µg/L 1/3 2025
Pfhxa 0.0040 µg/L 1/3 2025
PFOS 0.0045 µg/L 1/3 2025
Pfpea 0.0046 µg/L 1/3 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.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Total Haloacetic Acids (HAA5)
45.6 µg/L 76%
of the EPA limit 60 µg/L
worst single sample: 82 µg/L
129/129 SYR4 2012–2019
Bromodichloromethane
25 µg/L
No EPA limit set
worst single sample: 29 µg/L
128/128 SYR4 2012–2019
Chloroform
72 µg/L
No EPA limit set
worst single sample: 93 µg/L
128/128 SYR4 2012–2019
Dibromochloromethane
9.5 µg/L
No EPA limit set
worst single sample: 14 µg/L
128/128 SYR4 2012–2019
TTHM
100 µg/L 125%
of the EPA limit, at the 95th percentile of samples — 80 µg/L
worst single sample: 120 µg/L
128/128 SYR4 2012–2019
Dichloroacetic Acid
19 µg/L
No EPA limit set
worst single sample: 28 µg/L
126/129 SYR4 2012–2019
Trichloroacetic Acid
28 µg/L
No EPA limit set
worst single sample: 50 µg/L
126/129 SYR4 2012–2019
Dibromoacetic Acid
2.75 µg/L
No EPA limit set
worst single sample: 4.1 µg/L
46/129 SYR4 2012–2019
Monochloroacetic Acid
5.375 µg/L
No EPA limit set
worst single sample: 24 µg/L
42/129 SYR4 2012–2019
Nitrate
3755 µg/L 38%
of the EPA limit 10000 µg/L
worst single sample: 3800 µg/L
26/30 SYR4 2012–2019
Bromoform
3.07 µg/L
No EPA limit set
worst single sample: 3.2 µg/L
23/128 SYR4 2012–2019
Lead
0.0020 mg/L 13%
of the EPA limit 0.0150 mg/L
 22/22 LCR 2025
Barium
19.5 µg/L 1%
of the EPA limit 2000 µg/L
worst single sample: 21 µg/L
11/11 SYR4 2012–2019
Fluoride
1083 µg/L 27%
of the EPA limit 4000 µg/L
worst single sample: 1200 µg/L
10/11 SYR4 2012–2019
Monobromoacetic Acid
1.2 µg/L
No EPA limit set
 7/129 SYR4 2012–2019
Copper
54.8 µg/L 4.2%
of the EPA limit 1300 µg/L
worst single sample: 57 µg/L
3/4 SYR4 2015–2016
Chromium
6 µg/L 6%
of the EPA limit 100 µg/L
 1/11 SYR4 2012–2019
Pentachlorophenol
0.1000 µg/L 10%
of the EPA limit 1 µg/L
 1/12 SYR4 2012–2018
Selenium
2 µg/L 4%
of the EPA limit 50 µg/L
 1/11 SYR4 2012–2019
81 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-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalArsenicAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndrinEthylbenzeneGross Beta Particle ActivityHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorNetfosaaNfdhaNmefosaaNitriteOxamylPFBSPfdaPfdoaPfeesaPfhpaPfhpsPFHXSPfmbaPfmpaPFNAPfpesPftaPftrdaPfunaPicloramSimazineStyreneTetrachloroethyleneThallium, TotalTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
JONATHAN A LOJA
Phone
7813830057
Email
[email protected]

Frequently asked questions about Cohasset Water Dept

Is Cohasset Water Dept tap water safe to drink?

EPA monitoring detected 24 contaminants in Cohasset Water Dept'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 Cohasset Water Dept's water?

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

How many people does Cohasset Water Dept serve?

Cohasset Water Dept reports serving 7,555 people in Massachusetts, per its EPA record.

Has Cohasset Water Dept had any water quality violations?

The EPA has 59 violations on file for Cohasset Water Dept, of which 3 are health-based (a contaminant limit or required treatment was breached) and 0 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.