Delaware water quality overview
Delaware's drinking water quality is good overall, with an average score of 76.7 out of 100 across 40 cities tested. The median score is 79.5, serving a total population of 842,068 residents. 83% of cities earned an A or B grade, indicating broadly strong water quality infrastructure across the state. PFAS "forever chemicals" were detected in 21 of 40 cities tested (53%). 13 cities exceed the 2024 EPA maximum contaminant levels. 1 city has lead levels exceeding the EPA action level of 15 ppb, often indicating aging infrastructure with lead service lines or lead solder. The state relies on a mix of water sources: 36 cities use groundwater while 4 draw from surface water such as rivers, lakes, and reservoirs.
Issues to watch in Delaware
Explore contaminants in Delaware
More contaminants tested in Delaware
Private-well water in Delaware
Based on USGS Powell Domestic-Well Database — 803 private wells sampled across Delaware. These wells are not regulated by the EPA; if you draw your tap from a private well, the public-system grade above does not apply to you.
Top industrial water polluters in Delaware
Industrial polluters nearby
The 10 facilities reporting the most pounds released to surface water in Delaware, 2023.
Total reported releases to surface water: 4,914,220 lbs
| Facility | Top chemical | To surface water (lbs/yr) |
|---|---|---|
DELAWARE CITY REFINERY DELAWARE CITY, DE19706 | Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 4,352,506 |
PERDUE FOODS LLC - GEORGETOWN PROCESSING PLANT GEORGETOWN, DE19947 | Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 561,613 |
V&S DELAWARE GALVANIZING LLC NEW CASTLE, DE19720 | Zinc compounds | 97 |
EDGE MOOR/HAY ROAD ENERGY CENTERS WILMINGTON, DE19809 | Ammonia | 3 |
Source: EPA Toxic Release Inventory (TRI) 2023
How Delaware cities scored
Worst Cities
Water quality across Delaware
Each dot is a city, colored by its water quality grade. Size reflects population served. Click any city to view its full water report.
40 cities in Delaware
| # | City | Grade | Score | Population | Violations |
|---|---|---|---|---|---|
| 1 | Delaware City | A+ | 96.9 | 3K | 3 |
| 2 | Slaughter Beach | A+ | 96.9 | 846 | 1 |
| 3 | Frederica | A | 92.5 | 950 | 19 |
| 4 | Selbyville | A | 92.4 | 4K | 8 |
| 5 | Dover Afb | A | 90.3 | 11K | 6 |
| 6 | Clayton | A- | 89.8 | 7K | 2 |
| 7 | Odessa | A- | 89.6 | 6K | 7 |
| 8 | Ocean View | A- | 87.5 | 683 | 20 |
| 9 | Milford | A- | 85.5 | 10K | 24 |
| 10 | Fenwick Island | A- | 85.5 | 8K | 13 |
| 11 | Bridgeville | B+ | 84.2 | 6K | 15 |
| 12 | Greenwood | B+ | 83.9 | 1K | 31 |
| 13 | Winterthur | B+ | 82.5 | 687 | 4 |
| 14 | Bethany Beach | B+ | 82.4 | 24K | 15 |
| 15 | Lincoln | B+ | 82.1 | 600 | 37 |
| 16 | Cheswold | B+ | 80.9 | 2K | 55 |
| 17 | Harrington | B+ | 80.8 | 4K | 38 |
| 18 | Hockessin | B+ | 80.5 | 231K | 8 |
| 19 | Middletown | B+ | 80.1 | 23K | 45 |
| 20 | Bear | B+ | 80 | 972 | 8 |
| 21 | Wilmington | B | 79.5 | 208K | 23 |
| 22 | Dagsboro | B | 79.4 | 934 | 61 |
| 23 | Milton | B | 78.7 | 3K | 32 |
| 24 | Delmar | B | 77.9 | 2K | 30 |
| 25 | Rehoboth Beach | B | 76.7 | 28K | 24 |
| 26 | Millville | B | 76.4 | 51K | 56 |
| 27 | Laurel | B | 76.4 | 5K | 94 |
| 28 | Magnolia | B | 76.2 | 1K | 56 |
| 29 | Davenport | B | 76.2 | 1K | 29 |
| 30 | Camden-Wyoming | B | 75.5 | 17K | 66 |
| 31 | Dover | B | 75.3 | 41K | 66 |
| 32 | New Castle | B- | 72.7 | 6K | 31 |
| 33 | Felton | B- | 70.4 | 2K | 95 |
| 34 | Dewey Beach | C+ | 66.8 | 31K | 32 |
| 35 | Smyrna | C | 63.1 | 13K | 61 |
| 36 | Newark | C- | 56.5 | 49K | 132 |
| 37 | Lewes | D+ | 52.8 | 12K | 55 |
| 38 | Millsboro | D | 49.4 | 10K | 156 |
| 39 | Seaford | F | 37.8 | 8K | 195 |
| 40 | Georgetown | F | 24 | 9K | 156 |
Browse Delaware by ZIP code
Look up water quality by ZIP code to find the systems serving your area.
View all Delaware ZIP codes →Frequently asked questions about Delaware's water
Is Delaware's tap water safe to drink?
Delaware's water quality varies by city. The statewide average grade is B (76.7/100). 83% of cities scored an A or B, while 10% received a D or F. Check your specific city for detailed results.
Which Delaware cities have the best water quality?
The top-rated cities are Delaware City (A+), Slaughter Beach (A+), Frederica (A). These cities scored highest based on violation history, lead levels, PFAS contamination, and regulatory compliance.
Which Delaware cities have the worst water quality?
The lowest-rated cities are Georgetown (F), Seaford (F), Millsboro (D). We recommend residents in these areas consider water filtration and review their city's specific contaminant data.
How many Delaware cities have PFAS in their water?
21 out of 40 cities tested positive for PFAS "forever chemicals" (53%). 13 cities exceed the 2024 EPA maximum contaminant levels. Reverse osmosis or activated carbon filters can help reduce PFAS exposure.
Do any Delaware cities have dangerous lead levels?
1 city exceeds the EPA lead action level of 15 ppb. Lead contamination typically comes from aging pipes and lead service lines rather than the water source itself. An NSF 53-certified filter can effectively remove lead from tap water.