We read 17 results from Wilmington Water Department’s 2024 water quality report. No results over a legal limit; 7 above a health goal or guideline.
Serves about 107,976 people · Water system ID DE0000663 · Read the district’s 2024 report (opens in a new tab)
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Results from the 2024 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Fluoridehighest measured · range 0.23 to 1.36 · Porter Filter Plant, highest of 2 sources · 2024 report, page 4 | 1.36 ppm | 1 ppm | 4 ppm | Above the health goal1.4x the health goal |
| Gross alpha (radioactivity)single sample · sampled 2020 · Entry points · 2024 report, page 5 | 0.14 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Lead90th percentile of homes tested, 1 over the action level · sampled 2023 · Customer taps · 2024 report, page 5 | 2 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal10x the health goal |
| PFOA (a PFAS)average · range ND to 13 · Entry points · 2024 report, page 5 | 6.98 ppt | 0.007 ppt | 4 ppt from 2029 | Above the federal limit that takes effect in 20291.7x the 4 ppt federal limit that takes effect in 2029Not a violation yet: EPA's 4 ppt limit is final, but water systems don't have to meet it until 2029. |
| PFOS (a PFAS)average · range ND to 3.7 · Entry points · 2024 report, page 5 | 2.78 ppt | 1 ppt | 4 ppt from 2029 | Above the health goal2.8x the health goal |
| Radium-228single sample · sampled 2020 · Entry points · 2024 report, page 5 | 0.84 pCi/L | 0.02 pCi/L | 5 pCi/L | Above the health goal44x the health goal |
| Total coliform bacteriahighest month · range ND to 2.7 · Distribution system · 2024 report, page 4 | 2.7 % positive | 0 % positive | 5 % positive | Above the health goalThe health goal is zero |
| Bariumsingle sample · sampled 2023 · Brandywine Filter Plant · 2024 report, page 4 | 0.05 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorinehighest measured · Distribution system · 2024 report, page 4 | 2.09 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · sampled 2023 · Customer taps · 2024 report, page 5 | 0.23 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 4 to 35 · Distribution system · 2024 report, page 4 | 36 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 9 to 79 · Distribution system · 2024 report, page 4 | 60 ppb | None set | 80 ppb | Below the legal limit |
| Nitrate (as N)highest measured · range 1.1 to 4 · Porter Filter Plant, highest of 2 sources · 2024 report, page 4 | 4 ppm | 10 ppm | 10 ppm | Below the health goal |
| PFNA (a PFAS)average · range ND to 4.3 · Entry points · 2024 report, page 5 | 2.52 ppt | None set | 10 ppt from 2029 | Below the legal limit |
| Turbidity (cloudiness)highest measured · range 0.03 to 0.12 · Porter Filter Plant, highest of 2 sources · 2024 report, page 4 | 0.12 NTU | None set | 1 NTU | Below the legal limit |
| Hardnessaverage · range 4.8 to 11.7 · Brandywine Filter Plant · 2024 report, page 5 | 7.49 gpg (128 ppm) | — | — | Hard |
| Sodiumaverage · Brandywine Filter Plant · 2024 report, page 5 | 24 ppm | None set | None | No health limit |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Wilmington Water Department’s water between Feb 2023 and Jan 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA9.9 pptFound in 8 of 8 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFBS3.6 pptFound in 4 of 8 samples · highest resultNo federal limit in force for this one
Source: EPA UCMR 5 occurrence data. The highest single result is shown; one high sample doesn’t mean every glass is that high.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
Fluoride
Found: Fluoride
What removes it: Reverse osmosis.
Radium and uranium
Found: Gross alpha (radioactivity), Radium-228
What removes it: Reverse osmosis.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
PFAS ("forever chemicals")
Found: PFOA (a PFAS), PFOS (a PFAS), PFOA (EPA testing)
What removes it: Reverse osmosis.
Bacteria and viruses
Found: Total coliform bacteria
What removes it: UV purification (and tell your utility).
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