DENNIS WATER DISTRICT
PWS ID: MA4075000 · SOUTH DENNIS, Massachusetts 02660
PFAS Detected
2 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
65,000
Total Violations
44
Health-Based Violations
7
Water Source
Groundwater
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 14,576
- County
- Barnstable
- School/Daycare
- No
- MCL Violations
- 7
- Monitoring Violations
- 34
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 7 | 2006 |
| TTHM | MR | 1 | 2008 |
| Total Haloacetic Acids (HAA5) | MR | 1 | 2008 |
| LASSO | MR | 1 | 2014 |
| 2,4-D | MR | 1 | 2014 |
| Endrin | MR | 1 | 2014 |
| Heptachlor epoxide | MR | 1 | 2014 |
| Heptachlor | MR | 1 | 2014 |
| Pentachlorophenol | MR | 1 | 2014 |
| Toxaphene | MR | 1 | 2014 |
| 2,4,5-TP | MR | 1 | 2014 |
| Methoxychlor | MR | 1 | 2014 |
| BHC-GAMMA | MR | 1 | 2014 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 1 | 2014 |
| Dalapon | MR | 1 | 2014 |
| Di(2-ethylhexyl) phthalate | MR | 1 | 2014 |
| Dinoseb | MR | 1 | 2014 |
| Endothall | MR | 1 | 2014 |
| Glyphosate | MR | 1 | 2014 |
| HEXACHLOROBENZENE | MR | 1 | 2014 |
| Hexachlorocyclopentadiene | MR | 1 | 2014 |
| OXAMYL | MR | 1 | 2014 |
| 2,3,7,8-TCDD | MR | 1 | 2014 |
| Picloram | MR | 1 | 2014 |
| Total Polychlorinated Biphenyls (PCB) | MR | 1 | 2014 |
| Chlordane | MR | 1 | 2014 |
| Simazine | MR | 1 | 2014 |
| Carbofuran | MR | 1 | 2014 |
| Diquat | MR | 1 | 2014 |
| ETHYLENE DIBROMIDE | MR | 1 | 2014 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 2 of 540 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFHpA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBA | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| HFPO-DA | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 4/9/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 4/9/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOS | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFPeS | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 4:2 FTS | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 8:2 FTS | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFMPA | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFPeA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 4/9/2024 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFHpS | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| lithium | 4/9/2024 | <9 µg/L | 9 µg/L | Not Detected |
| PFHxS | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 4/9/2024 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| NEtFOSAA | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTrDA | 4/9/2024 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 4/9/2024 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFEESA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFNA | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFBS | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| lithium | 4/9/2024 | <9 µg/L | 9 µg/L | Not Detected |
| PFDoA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| ADONA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 4/9/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 4/9/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOA | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFNA | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHpS | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBS | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOS | 4/9/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHpA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFEESA | 4/9/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTrDA | 4/9/2024 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| NEtFOSAA | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 4/9/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTA | 4/9/2024 | <0.008 µg/L | 0.008 µg/L | Not Detected |
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025.
PFAS data from EPA UCMR5 monitoring program (2023-2025).
This data is provided for informational purposes only.