All 35 systems had enough required samples to calculate a yearly average. 12 had at least one yearly average at or above a study benchmark; 23 did not.
EPA-based study benchmark: the unrounded cutoff this research uses to reproduce EPA’s January 2026 technical-assistance classification around the April 2024 federal levels. It is not a current standard or compliance finding and cannot determine household exposure or health risk.
Find your water system
ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
System counts in Delaware
Each count shows how many included water systems had a yearly average at or above the named study benchmark.
| Study benchmark | Systems at or above benchmark | Water systems included | Percent |
|---|---|---|---|
| PFOA: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 9 | 35 | 25.7% |
| PFOS: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 8 | 35 | 22.9% |
| PFHxS: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 35 | 0.0% |
| PFNA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 1 | 35 | 2.9% |
| HFPO-DA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 35 | 0.0% |
| Hazard Index: 1.5 study benchmark with at least two detected components (reproduces EPA classification around 1) | 1 | 35 | 2.9% |
Community water systems with complete monitoring
“Complete monitoring” means at least one sampling location had all required samples needed for a yearly average. Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study benchmark result |
|---|---|---|---|---|---|
| ARTESIAN NORTHERN SUSSEX REGIONAL | DE0020003 | 5,511 | Ground water | 3 | Below all study benchmarks |
| ARTESIAN WATER COMPANY | DE0000552 | 231,114 | Surface water purchased | 22 | At or above a study benchmark |
| BAYSIDE PUMP DISTRICT | DE00A0837 | 8,400 | Ground water | 2 | Below all study benchmarks |
| BETHANY BAY PUMP DISTRICT | DE0000221 | 51,000 | Ground water | 5 | At or above a study benchmark |
| BETHANY BEACH WATER DEPARTMENT | DE0000556 | 12,000 | Ground water | 1 | Below all study benchmarks |
| BRIDGEVILLE WATER DEPARTMENT | DE0000559 | 6,000 | Ground water | 3 | Below all study benchmarks |
| CAMDEN PUMP DISTRICT | DE0000124 | 17,208 | Ground water | 5 | Below all study benchmarks |
| CAMDEN WYOMING SEWER AND WATER AUTHORITY | DE0000563 | 5,000 | Ground water | 3 | Below all study benchmarks |
| CHURCH CREEK | DE00A0428 | 9,654 | Ground water | 5 | Below all study benchmarks |
| DELMAR UTILITY COMM (TN OF DELMAR) | DE0000567 | 2,027 | Ground water | 1 | Below all study benchmarks |
| DEWEY BEACH WATER DEPARTMENT | DE0000825 | 31,000 | Ground water purchased | 1 | At or above a study benchmark |
| DOVER AIR FORCE BASE | DE0000579 | 11,000 | Ground water | 1 | Below all study benchmarks |
| DOVER WATER DEPARTMENT | DE0000571 | 39,491 | Ground water | 16 | Below all study benchmarks |
| EAST NCC DISTRICT | DE00A0334 | 5,538 | Ground water | 2 | Below all study benchmarks |
| GARRISON LAKE PUMP DISTRICT | DE0000004 | 17,148 | Ground water | 3 | Below all study benchmarks |
| GEORGETOWN WATER DEPARTMENT | DE0000592 | 7,259 | Ground water | 2 | At or above a study benchmark |
| LAUREL WATER DEPARTMENT | DE0000597 | 3,984 | Ground water | 1 | Below all study benchmarks |
| LEWES BOARD OF PUBLIC WORKS | DE0000602 | 9,627 | Ground water | 1 | At or above a study benchmark |
| LONG NECK WATER COMPANY | DE0000625 | 11,000 | Ground water | 4 | Below all study benchmarks |
| MIDDLETOWN WATER DEPARTMENT, DE | DE0000614 | 17,700 | Surface water purchased | 2 | Below all study benchmarks |
| MILFORD WATER DEPARTMENT | DE0000616 | 9,800 | Ground water | 5 | Below all study benchmarks |
| MILLSBORO WATER DEPARTMENT | DE0000622 | 8,568 | Ground water | 1 | Below all study benchmarks |
| MUNICIPAL SERVICES COMMISSION | DE0000634 | 5,549 | Ground water | 1 | Below all study benchmarks |
| NEWARK WATER DEPARTMENT, DE | DE0000630 | 40,000 | Surface water | 2 | At or above a study benchmark |
| NORTH WEST PUMP DISTRICT | DE00A0347 | 4,149 | Ground water | 3 | Below all study benchmarks |
| REHOBOTH BEACH WATER DEPARTMENT | DE0000723 | 25,000 | Ground water | 3 | At or above a study benchmark |
| REHOBOTH PUMP DISTRICT | DE0000991 | 81,417 | Ground water | 12 | Below all study benchmarks |
| SEAFORD WATER DEPARTMENT | DE0000246 | 6,699 | Ground water | 2 | Below all study benchmarks |
| SMYRNA WATER DEPARTMENT | DE0000657 | 11,813 | Ground water | 3 | At or above a study benchmark |
| SOUTH BETHANY | DE00A0323 | 18,215 | Ground water | 3 | At or above a study benchmark |
| STAGE VILLAGE MHC | DE0000569 | 93 | Ground water | 1 | At or above a study benchmark |
| SUEZ WATER DELAWARE | DE0000564 | 100,495 | Surface water | 2 | At or above a study benchmark |
| SUSSEX SHORES WATER COMPANY | DE0000557 | 12,450 | Ground water | 2 | Below all study benchmarks |
| SWANN KEYS | DE0000465 | 1,764 | Ground water | 1 | Below all study benchmarks |
| WILMINGTON WATER DEPARTMENT | DE0000663 | 107,976 | Surface water | 2 | At or above a study benchmark |
What is included
Each active community water system with enough required samples for a yearly average is counted once, even if it is linked with several ZIP codes. This does not mean every home was tested. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Delaware's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.