Who supplies Nampa’s water
Nampa water report, by the numbers
We could not access the City of Nampa’s own water quality report while preparing this guide, so the readings below come from EWG and EPA rather than the city’s latest Consumer Confidence Report. Check the city’s report for current numbers, hardness and lead results.
| What was measured | Result | Federal limit | EWG guideline | Year · source |
|---|---|---|---|---|
| Uranium Reported in pCi/L, a different unit from the µg/L used in most Consumer Confidence Reports. | 9.49 pCi/L | EPA MCL is 30 µg/L (EWG lists 20 pCi/L) | 0.43 pCi/L | 2018–2023 avgEWG Tap Water Database |
| Arsenic | 4.74 ppb | 10 ppb | 0.004 ppb | 2021–2023 avgEWG Tap Water Database |
| Nitrate | 2.22 ppm | 10 ppm | 0.14 ppm | 2021–2023 avgEWG Tap Water Database |
| Chromium-6 (hexavalent) | 2.62 ppb | No federal limit for chromium-6 (total chromium 100 ppb) | 0.02 ppb | 2013–2023 avgEWG Tap Water Database |
| Radium 226 + 228 | 0.53 pCi/L | 5 pCi/L | 0.05 pCi/L | 2018–2023 avgEWG Tap Water Database |
| TTHMs | 4.1 ppb | 80 ppb | 0.15 ppb | 2021–2023 avgEWG Tap Water Database |
| HAA5 | 1.1 ppb | 60 ppb | 0.1 ppb | 2021–2023 avgEWG Tap Water Database |
| Fluoride | 0.582 ppm | 4 ppm | — | 2021–2023 avgEWG Tap Water Database |
| Vanadium | 11.4 ppb | No federal limit | 21 ppb | 2013–2023 avgEWG Tap Water Database |
EWG figures are utility annual averages for 2021–2023 (radiological 2018–2023) from tests the utilities report to Idaho DEQ. EWG health guidelines are health-based goals, not legal limits. “ND” means not detected.
What stands out
- Uranium averaged 9.49 pCi/L (2018–2023), the highest of the city systems in our Treasure Valley guides. EWG reports uranium in pCi/L; the federal limit is 30 µg/L, so the two numbers are not directly comparable.
- Chromium-6 averaged 2.62 ppb. There is no separate federal limit for chromium-6; EWG’s health guideline is 0.02 ppb.
- Disinfection byproducts are low: TTHMs averaged 4.1 ppb against an 80 ppb limit.
About the 2026 uranium notice on a Nampa state campus
In June 2026, Idaho Health and Welfare reported uranium above the federal limit in some buildings on the Southwest Idaho Treatment Center campus in Nampa that use the campus’s own on-site well. That is not City of Nampa water: the residential halls and State Hospital West on the same campus are on city water, and the state planned to connect another building to the city system.
Private wells around Nampa
IDWR counted 5,343 documented domestic wells in Canyon County (2019, cited in a Boise State/IDWR uranium study). Wells aren’t covered by the city’s testing. Southwest District Health serves Canyon County and offers free sample bottles plus a Wednesday courier to the state lab; see how to test your water.
What treatment actually helps
- Drinking water (uranium, arsenic, nitrate, chromium-6): under-sink reverse osmosis.
- Scale and spotting: a whole-home softener, sized to your measured hardness.
- Chlorine taste and odor: whole-home carbon filtration.
On a private well?
Canyon County is served by Southwest District Health
SWDH offers free sample bottles and a $10 courier that carries samples to the state lab on Wednesdays only (drop-off cutoffs: Payette 9:30 a.m., Emmett 10:30 a.m., Caldwell 11:00 a.m.). Lab fees are billed separately.
Treating Nampa water
Get an honest recommendation
Tell us what you’re noticing and we’ll recommend only what your water needs, with one written price. If you don’t need a system, we’ll say so.
Frequently asked questions
Is Nampa tap water safe to drink?
Does Nampa water have uranium?
Where can I find Nampa’s water quality report?
Sources
- City of Nampa, water quality
- EWG Tap Water Database, City of Nampa (ID3140080)
- EPA ECHO, City of Nampa (ID3140080)
- Idaho DHW, Southwest Idaho Treatment Center campus water (June 26, 2026)
- Boise State University / IDWR uranium study (October 2019)
- EPA, Find Your Consumer Confidence Report
Honest Water Boise is not affiliated with any utility, Idaho agency or EWG. This guide summarizes public reports for general information and does not replace your utility’s Consumer Confidence Report or a lab test of your own water.
