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Wilmington Water Department water quality report, rewritten

Serves
107,976
Connections
37,915
Water source
Surface water
Based in
Wilmington, DE
County
New Castle
Owner
Local government
The 23 ZIP codes it serves

19082, 19701, 19702, 19707, 19708, 19710, 19720, 19732, 19801, 19802, 19803, 19804, 19805, 19806, 19807, 19808, 19809, 19810, 19850, 19880, 19884, 19898, 19899

PWSID DE00006632026 edition · EPA data

Read this first

  • PFOA (above the health goal) was found in eight of 8 samples, highest 9.9 ppt. Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.

1 health-based violation since 2016. Details are below.

What handles it

What was found

Highlighted: above the health goal, or EPA’s health benchmark where there is no goal. Circled: above the legal limit in at least one sample, or the action level. Every scale puts that line at its middle.

PFOA (above the health goal)

Comes from the source

9.9 (above the legal limit in at least one sample)ppt

Highest of 8 samples; found in eight

Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.

What handles it

  • NSF/ANSI 53Look for: PFOA ReductionSame claim, other certifiers’ wording: Total PFAS Reduction; Perfluorooctanoic Acid (PFOA)
  • NSF/ANSI 58Look for: Perfluorooctanoic Acid (PFOA)

NSF’s PFAS claims are tested to below 20 ppt. EPA’s limit is 4.0 ppt, and EPA says no certification yet shows a filter reaching its levels.

EPA UCMR 5, samples taken from Feb. 8, 2023 to Jan. 31, 2024. Each blue tick is one sample where it was found.

PFBS

Comes from the source

3.6ppt

Highest of 8 samples; found in four

Below EPA’s hazard index benchmark of 2,000 ppt. PFBS has no legal limit or health goal of its own.

What handles it

EPA UCMR 5, samples taken from Feb. 8, 2023 to Nov. 7, 2023. Each blue tick is one sample where it was found.

Also found, with no federal limit

EPA measured these PFAS to learn how often they occur. None has a legal limit or a health goal yet.

CompoundHighest sampleFound inCertification claim
PFPeA32.2 ppt8 of 8None covers it
PFHxA21.1 ppt8 of 8None covers it
PFBA14.1 ppt7 of 8None covers it
PFHpA8.4 ppt5 of 8NSF/ANSI 53: Total PFAS Reduction

Tested and not found

Below EPA’s minimum reporting level in every sample taken from Feb. 8, 2023 to Jan. 31, 2024. Not found means not measured above that level, which is not the same as zero.

All 25 compounds tested and not found
  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • Lead
  • Lithium
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpS
  • PFHxS
  • PFMBA
  • PFMPA
  • PFNA
  • PFOS
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Long Term 2 Enhanced Surface Water Treatment RuleFailure Submit Treatment Requirement RptOct. 1, 2017—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown.

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

At the tap, or for the whole house?

These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. How whole-house systems compare.

Compare five-year costs

Filters with those claims on a certifier’s listing

TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

What this report cannot tell you

  • Levels of everything else. Federal bulk data carries results for PFAS, lithium, lead and copper, and violations for the rest. Nitrate, arsenic, disinfection byproducts and other levels are in Wilmington Water Department’s own annual report, which it must send you every year.
  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
  • Anything after the latest data. SDWIS data is from 2026 Q2; UCMR 5 samples are from Feb. 8, 2023 to Jan. 31, 2024.

What to do next

  1. Read up on PFOA

    What each one does to health, where it comes from, and the certification claim that addresses it.

    About PFOA

  2. Get the utility’s own report

    Wilmington Water Department must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.

    How to read it

  3. Test your own tap for lead

    Your service line, solder and fixtures decide the lead at your faucet, not the utility’s average.

    Lead in your water: what to do

  4. Compare certified filters

    What the filters certified for these results cost over five years, cartridges included.

    Compare five-year costs

Other Delaware utilities

All Delaware utilities

Sources