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Getting your well water tested in Idaho

Idaho has free or low-cost well testing. Across the state, the ones worth testing for are arsenic, lead and manganese, plus bacteria and nitrate every year.

Compare lab tests Find my county

About 423,000 people in Idaho get their water from a private well, about 1 in 4 residents.

Three ways to get tested, cheapest first.

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A lab Idaho certifies

The state's list of labs certified for drinking water. Many sell bottles you pick up or get by mail, and their results count for a home sale or loan.

Labs certified by Idaho
3

A mail-in kit

Order online, fill the bottles at your kitchen tap and get results by email in about a week. Full well tests run about $210 to $220.

Compare kits for Idaho

Look up a well's drilling report in Idaho

What turns up in Idaho wells.

Share of tested wells over the limit, from lab tests the USGS, EPA and state agencies collected since 2000. Your own well needs its own test.

Tested wells over the limit, statewide
Arsenic15%398 of 2,610Lead11%142 of 1,323Manganese9%239 of 2,543Nitrate4%121 of 2,859Fluoride2%51 of 2,284Uranium1%2 of 303Radon0%0 of 12
GermsTest every year, whatever the chart says
Coliform bacteria60%372 of 616
StainsNot a health risk
Iron stains14%345 of 2,491

Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+

Lab results: Water Quality Portal (USGS and EPA)

Where it shows up most

  • Nitrate shows up most in Washington County (about 1 in 4 wells), Elmore County (about 1 in 8 wells), Canyon County (about 1 in 9 wells).
  • Arsenic shows up most in Owyhee County (about 6 in 10 wells), Twin Falls County (about 5 in 10 wells), Washington County (about 4 in 10 wells).

Find your county.

7 counties have a full report with local test results and well depths.

AdaBinghamBonnerCanyonJeffersonKootenaiTwin Falls
Every county in Idaho: people on wells and typical depth
CountyPeople on private wellsShare of residentsTypical well depth
Ada County52,19911%–
Canyon County48,74621%–
Bingham County24,55751%–
Bonner County23,29849%–
Twin Falls County22,77825%–
Kootenai County21,22912%–
Jefferson County20,62267%–
Bonneville County15,40912%–
Bannock County11,67613%–
Payette County11,48545%–
Cassia County11,35846%–
Gem County10,99057%–
Madison County10,80520%–
Minidoka County9,52644%–
Jerome County9,51039%–
Latah County8,59822%–
Idaho County8,12949%–
Gooding County7,05945%–
Fremont County6,67450%–
Owyhee County6,42554%–
Elmore County6,29922%–
Teton County5,92451%–
Blaine County5,77024%–
Valley County5,58248%–
Washington County5,41452%–
Boundary County4,79940%–
Franklin County4,68833%–
Lemhi County4,49356%–
Benewah County4,43947%–
Nez Perce County4,36810%–
Boise County4,32557%–
Clearwater County3,59241%–
Adams County2,61860%–
Caribou County2,60337%–
Power County2,58733%–
Shoshone County2,55019%–
Lincoln County2,53950%–
Custer County2,48958%–
Oneida County2,12046%–
Bear Lake County1,89330%–
Butte County1,39054%–
Lewis County93827%–
Camas County54751%–
Clark County30038%–

Questions people ask about well water in Idaho

Does Idaho require private wells to be tested?

Idaho doesn't require routine testing of existing private wells. Keeping a well safe is up to the owner, so test for bacteria and nitrate every year.

Where can I get my well water tested in Idaho?

DHW offers free private well water testing kits through Idaho Health Tools, limited to one kit per household every five years. Otherwise, use a lab certified by Idaho for drinking water. The state's list is linked on this page.

Where these numbers come from

  • How many people use wells: EPA estimates from the 2020 Census.
  • Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000.
  • State programs and links: Department of Health and Welfare.