Tap Water Quality Report

Tap water quality in WILMINGTON, Delaware

Served by 2 public water systems. 208,471 residents.

Average score 56/100
Utilities 2
Population 208,471
Quick answer

Tap water in WILMINGTON, Delaware receives a grade of F (56/100) from TapWaterSafety.org. It's served by 2 public water systems, primarily WILMINGTON WATER DEPARTMENT. 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. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.

Data sources for this grade: utilities.csv EWG Tap Water Database ⓘ How did we get this rating?

What's in WILMINGTON's tap water

Top water quality concerns identified by the EPA and Environmental Working Group across the utilities serving WILMINGTON.

PFAS contamination

Severe concern

Perfluorooctanoic 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 concern

Haloacetic 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 concern

Total 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 concern

Haloacetic acids (HAA5) detected at 24.4 ppb, 244x above the EWG health guideline of 0.1 ppb.

Recommended filters for WILMINGTON

Filters matched to the specific contaminants in WILMINGTON's water supply.

Reverse Osmosis or NSF P473 certified carbon

$80-$750

Activated carbon and RO are the only technologies proven to remove PFAS at certified levels.

AquaTru Countertop Reverse Osmosis
$449-$599 NSF 42, 53, 58, 401, P473
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Aquasana OptimH2O Reverse Osmosis + Claryum
$429-$549 NSF 42, 53, 58, 401, P473
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Waterdrop G3P800 Tankless RO
$600-$750 NSF 58, 372
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Waterdrop N1 Countertop RO
$249-$329 NSF 58, 372
View on retailer →
Clearly Filtered Pitcher Filter
$80-$95 NSF 42, 53, 401, P473
Editorial pick · affiliate link coming soon

Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.

All contaminants detected in WILMINGTON's tap water

Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. 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
19.2 ppt 0.09 4.0 100 100 0.007 EPA violation
Perfluorononanoic acid (PFNA)
PFAS
8.2 ppt 0.006 10.0 1367× over
Haloacetic acids (HAA9)
Disinfection byproduct
43.0 ppb 0.06 717× over
Total trihalomethanes (TTHMs)
Disinfection byproduct
47.9 ppb 0.15 80.0 100 319× over
Haloacetic acids (HAA5)
Disinfection byproduct
31.6 ppb 0.1 60.0 60 316× over
Perfluorodecanoic acid (PFDA)
PFAS
1.55 ppt 0.006 258× over
Bromodichloromethane
Disinfection byproduct
12.8 ppb 0.06 213× over
Bromochloroacetic acid
Disinfection byproduct
3.63 ppb 0.02 182× over
Perfluoroundecanoic acid (PFUnA)
PFAS
0.9 ppt 0.006 150× over
Trichloroacetic acid
Disinfection byproduct
13.6 ppb 0.1 136× over
Dichloroacetic acid
Disinfection byproduct
16.8 ppb 0.2 84× over
Chloroform
Disinfection byproduct
30.6 ppb 0.4 76× over
Dibromochloromethane
Disinfection byproduct
3.99 ppb 0.1 40× over
Dibromoacetic acid
Disinfection byproduct
0.827 ppb 0.03 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
Radium, combined (-226 and -228)
Radiological
0.83 pCi/L 0.05 5.0 17× over
Chromium (hexavalent)
Heavy metal
0.316 ppb 0.02 16× 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
Manganese
Heavy metal
28.3 ppb 100.0 50 80 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
Perfluorobutanoic Acid (PFBA)
PFAS
29.5 ppt 1000.0 Below guideline
Selenium
Heavy metal
0.69 ppb 30.0 50.0 20 40 30 Below guideline
Perfluorohexanoic Acid (PFHxA)
PFAS
22.9 ppt 1000.0 Below guideline
Perfluoropentanoic Acid (PFPeA)
PFAS
22.8 ppt 1000.0 Below guideline
Perfluoroheptanoic acid (PFHPA)
PFAS
19.6 ppt 1000.0 Below guideline
2,4-D
Pesticide/Herbicide
0.23 ppb 20.0 70.0 Below guideline
Monochloroacetic acid
Disinfection byproduct
0.491 ppb 53.0 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
2.59 ppt 2000.0 Below guideline
Strontium
Radiological
0.167 ppb 1500.0 Below guideline
Fluoride
Inorganic
0.713 ppm 4.0 1.5 1.5 Below guideline
Bromide
Other
8.15 ppb 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, California OEHHA PHGs, EWG Tap Water Database.

Treatment plant contact info

For service issues, water quality concerns, or to request a Consumer Confidence Report from WILMINGTON WATER DEPARTMENT.

Treatment Plant

FacilityBRANDYWINE PLANT