We read 10 results from Longmont City of’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 102,866 people · Water system ID CO0107485 · Read the district’s 2025 report (opens in a new tab)
Open this district in the water lookupCompare with your own test results, see the district map and get matched filters.
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 |
|---|---|---|---|---|
| Lead90th percentile of 52 homes tested, 2 over the action level · Customer taps · 2025 report, page 8 | 1.85 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal9.3x the health goal |
| Bariumsingle sample · sampled 2020 · Treated water · 2025 report, page 8 | 0.01 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorinehighest measured · range 0.59 to 1.57 · Distribution system · 2025 report, page 8 | 1.14 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 52 homes tested, 0 over the action level · Customer taps · 2025 report, page 8 | 0.05 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 16.3 to 25.2 · Distribution system · 2025 report, page 8 | 22.5 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 21.2 to 39.2 · Distribution system · 2025 report, page 8 | 33.1 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridesingle sample · sampled 2021 · Treated water · 2025 report, page 8 | 0.67 ppm | 1 ppm | 4 ppm | Below the health goal |
| Turbidity (cloudiness)highest measured · range 0.02 to 0.07 · Treatment plants · 2025 report, page 8 | 0.07 NTU | None set | 1 NTU | Below the legal limit |
| Hardnessaverage · range 1.11 to 1.46 · Treated water · 2025 report, page 9 | 1.27 gpg (21.7 ppm) | — | — | Soft |
| Sodiumaverage · range 11.8 to 15 · Treated water · 2025 report, page 9 | 13.4 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 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.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
More districts: Colorado water quality · All states · Something look wrong? Tell us