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Tap water quality report

Dennis Water District

EPA monitoring tested this supplier for 92 contaminants and detected 8. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

92
contaminants tested
8
detected
65,000
people served
7
health-based violations
Massachusetts rankingsLead in MassachusettsPFAS in Massachusetts
Water source
Ground water
Ownership
Local government
Counties served
Barnstable

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.

7
health-based violations
41
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 2006-12-01 → 2006-12-31
MCL Health-based Resolved 2006-12-01 → 2006-12-31
MCL Health-based Resolved 2005-11-01 → 2005-11-30
MCL Health-based Resolved 2005-11-01 → 2005-11-30
MCL Health-based Archived 2003-11-01 → 2003-11-30
MCL Health-based Archived 2000-06-01 → 2000-06-30
MCL Health-based Archived 2000-06-01 → 2000-06-30
MR Monitoring Archived 2014-01-01 → 2016-12-31
MR Monitoring Archived 2014-01-01 → 2016-12-31
MR Monitoring Archived 2014-01-01 → 2016-12-31

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
Pfhxa 0.0056 µg/L 1/18 2024
Pfpea 0.0051 µg/L 1/18 2024

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
Nitrate
2200 µg/L 22%
of the EPA limit 10000 µg/L
worst single sample: 2420 µg/L
134/156 SYR4 2012–2019
TTHM
13 µg/L 16%
of the EPA limit 80 µg/L
worst single sample: 14 µg/L
57/58 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
4.1 µg/L 6.8%
of the EPA limit 60 µg/L
worst single sample: 5.5 µg/L
32/56 SYR4 2012–2019
Barium
46 µg/L 2.3%
of the EPA limit 2000 µg/L
worst single sample: 100 µg/L
21/29 SYR4 2012–2018
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 15/15 LCR 2023
Fluoride
550 µg/L 14%
of the EPA limit 4000 µg/L
 1/29 SYR4 2012–2018
84 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, TotalArsenicAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebEthylene DibromideEndrinEthylbenzeneHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
DAVID A LARKOWSKI
Phone
5083983351
Email
[email protected]

Frequently asked questions about Dennis Water District

Is Dennis Water District tap water safe to drink?

EPA monitoring detected 8 contaminants in Dennis Water District'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 Dennis Water District's water?

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

How many people does Dennis Water District serve?

Dennis Water District reports serving 65,000 people in Massachusetts, per its EPA record.

Has Dennis Water District had any water quality violations?

The EPA has 41 violations on file for Dennis Water District, of which 7 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.