Water Quality Report · Updated October 07, 2026
WILMINGTON WATER DEPARTMENT
WILMINGTON WATER DEPARTMENT delivers tap water graded D (59/100) by TapWaterSafety.org. The utility serves approximately 107,976 residents in WILMINGTON, Delaware using surface water. The most significant water quality concerns are: PFAS contamination; Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline. For questions, the utility can be reached at 302-576-3017.
Is WILMINGTON tap water safe to drink?
WILMINGTON WATER DEPARTMENT delivers tap water that earns a grade of D (59/100) from TapWaterSafety.org — a below-average rating, with multiple concerns including pfas contamination.
The utility serves 107,976 residents in WILMINGTON, drawing from surface water.
Public testing data identifies 16 contaminants in this water above EWG's health-based guidelines, including: Perfluorooctanoic acid (PFOA), Haloacetic acids (HAA9), Total trihalomethanes (TTHMs), Haloacetic acids (HAA5), Bromochloroacetic acid, Bromodichloromethane, Trichloroacetic acid, Chloroform, Dichloroacetic acid, Dibromochloromethane, Nitrate, Nitrate and nitrite, Chromium (hexavalent), Radium, combined (-226 and -228), Dibromoacetic acid, Chlorate. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
EPA compliance record
Official U.S. EPA records for WILMINGTON WATER DEPARTMENT (system ID DE0000663) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Revised Total Coliform Rule | Missed testing | 08/01/2023 | Open |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Quick actions for WILMINGTON residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for WILMINGTON WATER DEPARTMENT.
PFAS contamination
Severe concernPerfluorooctanoic acid (PFOA) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 43.0 ppb, 717x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 38.1 ppb, 254x above the EWG health guideline of 0.15 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 24.4 ppb, 244x above the EWG health guideline of 0.1 ppb.
Contact WILMINGTON WATER DEPARTMENT
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for WILMINGTON
Filters matched to the specific contaminants in this water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
Score breakdown
This utility's overall score of 59/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Perfluorooctanoic acid (PFOA) PFAS |
7.05 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | EPA violation |
| Haloacetic acids (HAA9) Disinfection byproduct |
43.0 ppb | 0.06 | — | — | — | — | — | 717× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
38.1 ppb | 0.15 | 80.0 | 100 | — | — | — | 254× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
24.4 ppb | 0.1 | 60.0 | 60 | — | — | — | 244× over |
| Bromochloroacetic acid Disinfection byproduct |
3.63 ppb | 0.02 | — | — | — | — | — | 182× over |
| Bromodichloromethane Disinfection byproduct |
9.87 ppb | 0.06 | — | — | — | — | — | 165× over |
| Trichloroacetic acid Disinfection byproduct |
12.2 ppb | 0.1 | — | — | — | — | — | 122× over |
| Chloroform Disinfection byproduct |
26.2 ppb | 0.4 | — | — | — | — | — | 65× over |
| Dichloroacetic acid Disinfection byproduct |
11.7 ppb | 0.2 | — | — | — | — | — | 58× over |
| Dibromochloromethane Disinfection byproduct |
2.83 ppb | 0.1 | — | — | — | — | — | 28× over |
| Nitrate Inorganic |
2.39 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 17× over |
| Nitrate and nitrite Inorganic |
2.38 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 17× over |
| Chromium (hexavalent) Heavy metal |
0.316 ppb | 0.02 | — | — | — | — | — | 16× over |
| Radium, combined (-226 and -228) Radiological |
0.67 pCi/L | 0.05 | 5.0 | — | — | — | — | 13× over |
| Dibromoacetic acid Disinfection byproduct |
0.309 ppb | 0.03 | — | — | — | — | — | 10× over |
| Chlorate Disinfection byproduct |
266.1 ppb | 210.0 | — | — | — | — | — | 1.3× over |
| Atrazine Pesticide/Herbicide |
0.0325 ppb | 0.1 | 3.0 | 0.1 | 100 | 0.15 | — | Below guideline |
| Simazine Pesticide/Herbicide |
0.03 ppb | 0.1 | 4.0 | — | — | — | — | Below guideline |
| Barium Heavy metal |
51.1 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Molybdenum Other |
1.54 ppb | 40.0 | — | — | — | — | — | Below guideline |
| 1,4-Dioxane Semi-volatile organic compound |
0.0125 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Manganese Heavy metal |
3.43 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Selenium Heavy metal |
0.69 ppb | 30.0 | 50.0 | 20 | 40 | 30 | — | Below guideline |
| Perfluoropentanoic Acid (PFPeA) PFAS |
11.7 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
9.49 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.431 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
7.3 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA) PFAS |
2.86 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.06 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.0446 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
1.68 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.128 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Bromide Other |
8.15 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.669 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Nitrite Inorganic |
0.00282 ppm | — | 1.0 | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
WILMINGTON WATER DEPARTMENT service area
This water system serves 1 community in New Castle County, Delaware. Click any city for its dedicated tap water quality page.
Find the right filter for WILMINGTON water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.