We read 9 results from Loudoun Water - Central System’s 2025 water quality report. No results over a legal limit or above a health goal.
Serves about 334,808 people · Water system ID VA6107350 · Read the district’s 2025 report (opens in a new tab)
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Results from the 2025 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 |
|---|---|---|---|---|
| Chloraminehighest running annual average · range 0.2 to 4.7 · Distribution system · 2025 report, page 14 | 2.98 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 10 | 0.11 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 3.6 to 34.9 · Distribution system · 2025 report, page 14 | 21 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 9.24 to 65 · Distribution system · 2025 report, page 14 | 40.7 ppb | None set | 80 ppb | Below the legal limit |
| Lead90th percentile of homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 10 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| PFOS (a PFAS)average · range ND to 1.9 · Trap Rock plant · 2025 report, page 11 | Not detected | 1 ppt | 4 ppt from 2029 | Not detected |
| Total coliform bacteriahighest month · Distribution system · 2025 report, page 14 | Not detected | 0 % positive | 5 % positive | Not detected |
| Turbidity (cloudiness)highest measured · Treatment plants · 2025 report, page 13 | 0.14 NTU | None set | 1 NTU | Below the legal limit |
| Sodiumhighest measured · Loudoun Water Trap Rock plant, highest of 2 sources · 2025 report, page 15 | 18.7 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.
What you can do
Nothing in this report is above a health goal or legal limit. If you’re bothered by taste, smell, hardness or spots, or your home has older pipes, the filter catalog and buyer questions can help you pick, and a test of your own tap shows what your plumbing adds.
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