Delaware Water Report Card: Worst Water Systems
The most contaminated public water systems in Delaware, ranked by PFAS levels, lead, and EPA violations from official EPA data.
Quick Answer
Municipal Services Commission has the highest PFAS in Delaware at 147.2 ppt (37x the EPA limit). Lewes Board Of Public Works has the highest lead at 26.5 ppb. The tables below rank the worst systems in each category so you can see how your water compares.
Highest PFAS Levels in Delaware
Public water systems in Delaware with the highest peak PFAS ("forever chemical") reading in EPA UCMR5 testing (2023-2025). The EPA enforceable limit for PFOA and PFOS is 4 ppt.
| # | Water System | Location | Peak PFAS (ppt) | Compounds | vs 4 ppt limit |
|---|---|---|---|---|---|
| 1 | Municipal Services Commission | New Castle · 5,549 served | 147.2 | 2 | 37x |
| 2 | Artesian Water Company | Newark · 231,114 served | 106 | 8 | 27x |
| 3 | Suez Water Delaware | Wilmington · 100,495 served | 40.6 | 7 | 10x |
| 4 | Wilmington Water Department | Wilmington · 107,976 served | 32.2 | 5 | 8x |
| 5 | Newark Water Department, De | Newark · 40,000 served | 25.3 | 8 | 6x |
| 6 | Georgetown Water Department | Georgetown · 7,259 served | 15 | 8 | 4x |
| 7 | Rehoboth Beach Water Department | Rehoboth Beach · 25,000 served | 14.9 | 6 | 4x |
| 8 | Bayside Pump District | Dover · 8,400 served | 13.5 | 2 | 3x |
| 9 | Stage Village Mhc | Dagsboro · 93 served | 12.7 | 5 | 3x |
| 10 | Dewey Beach Water Department | Frankford · 31,000 served | 11 | 3 | 3x |
| 11 | Smyrna Water Department | Smyrna · 11,813 served | 9.8 | 5 | 2x |
| 12 | Lewes Board Of Public Works | Lewes · 9,627 served | 9.5 | 2 | 2x |
Highest Lead Levels in Delaware
Community water systems in Delaware with the highest 90th-percentile lead result under the EPA Lead and Copper Rule. The EPA action level is 15 ppb; there is no safe level of lead for children.
| # | Water System | Location | Lead 90th-pctile (ppb) | vs 15 ppb |
|---|---|---|---|---|
| 1 | Lewes Board Of Public Works | Lewes · 9,627 served | 26.5 | 1.8x over |
| 2 | Millsboro Water Department | Millsboro · 8,568 served | 17.5 | 1.2x over |
| 3 | Blades, Town Of | Blades · 1,200 served | 13 | within |
| 4 | Harrington Water Department | Harrington · 3,562 served | 12.5 | within |
| 5 | Milton Water Department | Milton · 3,200 served | 8.8 | within |
| 6 | Dover Air Force Base | Dover · 11,000 served | 7.8 | within |
| 7 | Bethany Bay Pump District | Dover · 51,000 served | 7.2 | within |
| 8 | Sussex Shores Water Company | Bethany Beach · 12,450 served | 6.9 | within |
| 9 | Felton Water Department | Felton · 1,591 served | 6.6 | within |
| 10 | Wilmington Water Department | Wilmington · 107,976 served | 5.6 | within |
| 11 | Bethany Beach Water Department | Bethany Beach · 12,000 served | 5.4 | within |
| 12 | Angola Beach Estates | Lewes · 1,400 served | 5.2 | within |
Most EPA Violations in Delaware
Community water systems in Delaware with the most health-based EPA Safe Drinking Water Act violations on record. A health-based violation means a contaminant exceeded its federal limit or required treatment was not applied.
| # | Water System | Location | Health-based violations |
|---|---|---|---|
| 1 | Selbyville Water Department | Selbyville · 3,502 served | 5 |
| 2 | Artesian Water Company | Newark · 231,114 served | 4 |
| 3 | Laurel Water Department | Laurel · 3,984 served | 3 |
| 4 | Artesian Southern Sussex Regional | Newark · 18,215 served | 3 |
| 5 | Millsboro Water Department | Millsboro · 8,568 served | 3 |
| 6 | Wilmington Water Department | Wilmington · 107,976 served | 1 |
| 7 | Blades, Town Of | Blades · 1,200 served | 1 |
| 8 | Rehoboth Pump District (Tui) | Dover · 81,417 served | 1 |
| 9 | Church Creek (Awc) | Newark · 9,654 served | 1 |
| 10 | Rehoboth Bay Community | Rehoboth Beach · 1,575 served | 1 |
| 11 | Broadkiln Beach Water Company (Tui) | Dover · 3,171 served | 1 |
| 12 | Seaford Water Department | Seaford · 6,699 served | 1 |
How This Report Card Is Built
PFAS rankings use EPA UCMR5 monitoring (2023-2025), showing each system's peak detection above the 4 ppt EPA limit. Lead rankings use the EPA Lead and Copper Rule 90th-percentile tap results. Violation counts come from the EPA Safe Drinking Water Information System (SDWIS) and count health-based violations. Lead and violation lists are limited to community water systems serving 1,000 or more people. Figures are the most severe on record and do not necessarily reflect current treated water.
Frequently Asked Questions
What is the most PFAS-contaminated water system in Delaware?
In EPA UCMR5 testing (2023-2025), Municipal Services Commission in New Castle had the highest recorded PFAS level in Delaware at 147.2 ppt - about 37x the EPA's 4 ppt limit for PFOA and PFOS.
Which Delaware water system has the highest lead levels?
Lewes Board Of Public Works in Lewes had the highest 90th-percentile lead result in Delaware under the EPA Lead and Copper Rule at 26.5 ppb - 1.8x the 15 ppb action level.
Which Delaware water system has the most EPA violations?
Selbyville Water Department in Selbyville has the most health-based EPA Safe Drinking Water Act violations on record in Delaware, with 5 violations.
Where does the Delaware water report card data come from?
PFAS figures come from EPA UCMR5 monitoring (2023-2025), lead from the EPA Lead and Copper Rule 90th-percentile tap results, and violations from EPA SDWIS health-based violation records. Figures are the most severe on record and do not necessarily reflect current treated water. Check your exact address at knowyourexposure.com.
What Delaware Residents Should Do
- Look up your exact address at knowyourexposure.com for your system's data
- See the full Delaware water quality overview
- If your system is listed, a certified filter (reverse osmosis for PFAS, NSF-53 for lead) reduces exposure at the tap. See the best water filters.