About 61% of the county's 11,310 residents. Rank 19 of 44 in Idaho.
95% range 1,175 to 1,667 private-well users (2010 base year). Rank 10 of 44 in Idaho.
Moderate potential (average indoor radon may be between 2 and 4 pCi/L). EPA says the map should not be used to decide whether an individual home needs testing.
Labs with an address in this county, from the official state lists on this site, matched by ZIP code.
What to test for in Owyhee County
Private wells are not regulated like public water: EPA advises owners to test their well every year for total coliform bacteria, nitrates, total dissolved solids and pH. Your state's own schedule:
- Idaho's Department of Health and Welfare (DHW) recommends testing for bacteria and nitrates once a year, and for other contaminants, including metals and chemicals, every 3 to 5 years. It suggests using the Idaho Private Well Water Drinking Map to see what may be present in your area and decide what to test for. source
- DHW's testing table lists arsenic, fluoride, selenium and uranium every 3 to 5 years; chloride, manganese and sulfate if your water tastes, smells or looks strange; pesticides and petroleum if you live in an agricultural area or have underground petroleum tanks; and manganese if you have a formula-fed infant under 6 months. source
Arsenic. USGS estimates that about 1,407 people using private wells in Owyhee County had arsenic above 10 µg/L, EPA's limit for public water (2010 base year; 95% range 1,175 to 1,667). USGS describes this kind of estimate as useful "for broad screening of the population at risk", so it says nothing certain about any one well. Arsenic has no taste or smell: test for it by name.
Radon. EPA puts Owyhee County in Zone 2: moderate potential (average indoor radon may be between 2 and 4 pCi/L). That map is about radon in indoor air, and EPA says it should not be used to decide whether an individual home needs testing. If radon is found in your air and you have a well, EPA suggests testing the water too: see radon in well water.
For anything specific to your home (farms nearby, old plumbing, a new baby, a smell or stain), use the which-tests checklist. When the results arrive, check your numbers against EPA's limits.
Show the numbers
| Item | Value | Note |
|---|---|---|
| Canyon County | 14,043 people (2010 base year) | |
| Twin Falls County | 7,858 people (2010 base year) | |
| Payette County | 2,477 people (2010 base year) | |
| Gem County | 2,130 people (2010 base year) | |
| Jefferson County | 1,904 people (2010 base year) | |
| Owyhee County (this county) | 1,407 people (2010 base year) |
USGS model estimate for broad screening, not a measurement of any well. Only a test tells you about your own well. Source: USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017), accessed 2026-11-01.
Testing programs and help in Idaho
- DHW offers free private well water testing (listed as available fall 2026) while funding is available. Idaho residents sign up through DHW's Idaho Health Tools website to have a free kit mailed home. The test covers nitrate, fluoride, arsenic, lead, uranium, manganese, chromium, nickel, copper, zinc, selenium, cadmium and barium, and results come with guidance on next steps. DHW says that because of the volume of kits being processed, it may take up to two months. source
- If your results show unsafe levels, DHW's Environmental Health Program can help you understand them and recommend how to fix the problem. DHW also publishes well water testing flow charts for next steps. source
- DHW's Groundwater Quality Near Me map shows private wells sampled since 2004 by the Idaho Department of Water Resources, the Department of Environmental Quality, the State Department of Agriculture and private well owners. Wells with results above a primary drinking water standard are shown in red. source
Buying a home with a well in Owyhee County
Loan test (FHA, VA, USDA) in Owyhee County, ID
- VA. Test results are valid for 90 days from the date the local health authority certifies them, unless the local authority says otherwise. VA’s chapter names no list of contaminants: the water must meet the local health authority’s requirements, or EPA guidelines where it has none. Your lender may ask for specific tests.
- FHA. A well test is required in the situations FHA’s handbook lists, among others, and the report may not be more than 180 days old at disbursement.
- USDA. Guaranteed loans need a water quality test for a private well, done by the local health authority or a state-certified lab, and no more than 180 days old at closing.
Lenders can ask for more (extra tests, a particular lab, who takes the sample): ask your lender before you book. Federal rules as read on Nov 3, 2026 source 1 source 2 source 3. Full comparison: VA, FHA and USDA well water test requirements. Loan test kits sold by mail, with price and days to results: kits compared.
State-certified labs in Owyhee County
None of the labs on our Idaho list has an address in Owyhee County. Labs elsewhere in the state may take samples by mail or courier: ask the lab, and check the hold time for bacteria before you send one.
Testing by mail from Owyhee County. Idaho Bureau of Laboratories, Drinking Water Analysis Submission Form, Private Well Owner, revised 08/21/2024 publishes these prices: Total coliform/E. coli $21; Nitrate $20; Nitrite $20 (checked 3 Nov 2026) source. All Idaho state-lab prices and how to get a kit.
See all Idaho labs in the finder and filter by the test you need and by labs that take homeowner samples.
- USGS, Estimated use of water in the United States, county-level data for 2015 (Dieter et al., ver. 2.0, 2018)
- USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017)
- U.S. EPA, Map of Radon Zones, county list (EPA 402/A-16/001)
- U.S. Census Bureau, 2020 ZCTA to county relationship file (lab ZIP codes to counties)
- Idaho Bureau of Laboratories - EPA Region 10 Drinking Water Certificates (2026 EPA Region 10 Drinking Water Certificate Microbiology LT2: letter of January 22, 2026; 2025 EPA Region 10 Drinking Water Certificate Chemistry: letter of March 24, 2025; 2025 EPA Region 10 Drinking Water Certificate Microbiology: letter of May 23, 2025)
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