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City water profile

Wilmington water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Wilmington, Delaware.

Median indexed hardness

79PPM

6 indexed ZIPs

Range 78.9–80.6 PPM

State comparison
24 PPM above
State hardness rank
#6 of 37
Matched utilities
2
Active health records
0

City summary

What the indexed records say

Wilmington has 6 published ZIP profiles across New Castle County. The indexed median is 79 PPM, compared with 55 PPM across Delaware.

Among the 37 Delawarecities with an indexed median, Wilmington ranks #6from highest to lowest. Across all 48 state ZIP profiles, available estimates run from 47.3to 82.4 PPM.

The 78.9–80.6 PPM range shows how much the available ZIP estimates vary within the city label.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard6 ZIPs
Hard0 ZIPs
Very hard0 ZIPs

6 of 6 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
5.9 miles
Profiles with evidence
6/6

Confidence labels

High: 0Moderate: 6Low: 0

Observation window: Jan 4, 2016 to Jun 10, 2026.

ZIP directory

Water reports in Wilmington

Open a ZIP for site-level provenance and measurements.

ZIP code

19801

Moderately Hard

78.9 PPM

Nearest site
5.5 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

19802

Moderately Hard

79 PPM

Nearest site
5.9 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

19803

Moderately Hard

80.6 PPM

Nearest site
5.5 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

19805

Moderately Hard

79.8 PPM

Nearest site
6.4 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

19806

Moderately Hard

79.1 PPM

Nearest site
6.3 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

19809

Moderately Hard

78.9 PPM

Nearest site
4.6 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Wilmington Water Department

PWSID DE0000663

Surface water
System population served
107,976
Last reported
Apr 30, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Veolia Water Delaware, Inc

PWSID DE0000564

Surface water
System population served
100,495
Last reported
Apr 30, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Compliance history

What EPA records show

No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.

RecordSystemPeriodStatus
Revised Total Coliform RuleDE0000663Aug 1, 2023Resolved

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in Wilmington

Is the water hard?

The indexed city median is 79 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.