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Updated 2026-10-15
County water report

Barnstable County Water Quality: 7 Cities Ranked by the Records

Barnstable County, Massachusetts: 7 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.

Find my systemOpen on the mapPrivate wells in Barnstable County
Across the county's systems

Highest result for each contaminant

One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.

Perfluorohexanesulfonic acid (PFHxS)Detected in 1 system of 7 tested10 ng/L federal MCL (2024) · US EPAHighest3.1 ng/L
Lead (90th percentile)Detected in 5 systems of 7 tested15 µg/L federal action level · US EPAHighest3.4 µg/L
Perfluorohexanoic acid (PFHxA)Detected in 1 system of 7 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest40.6 ng/L
Perfluorobutanoic acid (PFBA)Detected in 1 system of 7 testedNo federal or state limit; shown for transparencyHighest12.7 ng/L
Perfluoroheptanoic acid (PFHpA)Detected in 1 system of 7 testedNo federal or state limit; shown for transparencyHighest7.7 ng/L
Perfluoropentanoic acid (PFPeA)Detected in 1 system of 7 testedNo federal or state limit; shown for transparencyHighest59.4 ng/L
25 substances tested, none detected in any systemShow

Tested in these 7 systems: BREWSTER WATER DEPARTMENT, CHATHAM WATER DEPARTMENT, FALMOUTH WATER DEPT, HARWICH WATER DEPARTMENT, ORLEANS WATER DEPARTMENT, PROVINCETOWN WATER DEPARTMENT, YARMOUTH WATER DEPARTMENT

  • 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
  • 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
  • 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
  • 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
  • Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
  • Lithium
  • N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
  • N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
  • Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
  • Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
  • Perfluoro-3-methoxypropanoic acid (PFMPA)
  • Perfluoro-4-methoxybutanoic acid (PFMBA)
  • Perfluorobutanesulfonic acid (PFBS)
  • Perfluorodecanoic acid (PFDA)
  • Perfluorododecanoic acid (PFDoA)
  • Perfluoroheptanesulfonic acid (PFHpS)
  • Perfluorononanoic acid (PFNA)
  • Perfluorooctanesulfonic acid (PFOS)
  • Perfluorooctanoic acid (PFOA)
  • Perfluoropentanesulfonic acid (PFPeS)
  • Perfluorotetradecanoic acid (PFTA)
  • Perfluorotridecanoic acid (PFTrDA)
  • Perfluoroundecanoic acid (PFUnA)
7 cities

Cities ranked by the records

Showing 6 of 7 cities · scores are system-level, not tap tests

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.

PFAS in Barnstable CountyPFAS detected in 1 of 7 cities; none had a sample above a 2024 EPA limit
4.0 ng/L federal MCL · PFOS, ng/LPFAS in Massachusetts
Lead

0of 7 cities above the 15 µg/L action level

Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.

Lead in Massachusetts
Who supplies the county

Largest water systems

  1. FalmouthFALMOUTH WATER DEPT · MA4096000
    97,551 served
  2. HarwichHARWICH WATER DEPARTMENT · MA4126000
    39,144 served
  3. South YarmouthYARMOUTH WATER DEPARTMENT · MA4351000
    38,900 served
  4. BrewsterBREWSTER WATER DEPARTMENT · MA4041000
    35,000 served
  5. ChathamCHATHAM WATER DEPARTMENT · MA4055000
    30,000 served
  6. ProvincetownPROVINCETOWN WATER DEPARTMENT · MA4242000
    22,250 served
  7. OrleansORLEANS WATER DEPARTMENT · MA4224000
    17,460 served
Questions

Frequently asked

How does Barnstable County tap water compare across cities?

PurityMap ranks 7 cities in Barnstable County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Harwich's main water system: HARWICH WATER DEPARTMENT · PWSID MA4126000 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many Barnstable County cities had a PFAS sample above a 2024 EPA limit?

None of the 7 Barnstable County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing. PFAS were detected below the limit in 1.

Is there lead in Barnstable County tap water?

Utilities report lead as a 90th-percentile result from home taps. 5 of 7 Barnstable County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

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