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Health problems are rare in tested Spokane County wells.

All 6 health checks came back rare here.

From 41 wells tested in Spokane County since 2000; your own well needs its own test. How to read this

Tested wells over the limit SpokaneWashington
Manganese0%0 of 24Nitrate0%0 of 18Uranium0%0 of 24Arsenic0%0 of 24Lead0%0 of 24Fluoride0%0 of 24
GermsTest every year, whatever the chart says
Coliform bacteria0%0 of 1E. coli0%0 of 1
StainsNot a health risk
Iron stains8%2 of 24

Not charted, because fewer than 10 wells were tested: radon (1).

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

Lab results: Water Quality Portal (USGS and EPA)

Who drinks from a well here

About 1 in 16 people 32,762 people

Nobody else tests these wells. Only you do.

People on wells: EPA researchers' 2020 estimate

Radon risk (a gas from rock)

Likely here. Test your home's air first.

Radon zones: EPA map

Here's how Spokane County compares with Washington and the counties around it.

Each result puts Spokane County next to the 7 counties that border it, on the chart's 0 to 50% scale.

All 6 health checks are rare in Spokane County.

Manganese0 of 24 wells over

None of the 24 wells tested here from 2000 to 2016 were over the EPA health advisory of 0.3 mg/L, against about 2 in 10 across Washington. At least half the results were too low for the lab to measure, and the top 1 in 10 were 0.0034 mg/L or more. Spokane County had none, while 8 of the 15 other Washington counties with 10 or more tested wells had at least one, leaving out 1 county whose results are likely overstated.

Spokane and its neighbors
Stevens39%
Bonner, ID7%
Kootenai, ID5%
Benewah, ID3%
Spokane0%
Whitman0%

Too few tested to show: Lincoln, Pend Oreille.

Manganese guide

Nitrate0 of 18 wells over

None of the 18 wells tested here from 2015 to 2019 were over the EPA limit of 10 mg/L, against about 2 in 10 across Washington. Half the results were under 1.0 mg/L, and the top 1 in 10 were 4.2 mg/L or more. Spokane County had none, while 8 of the 15 other Washington counties with 10 or more tested wells had at least one, leaving out 1 county whose results are likely overstated.

Spokane and its neighbors
Kootenai, ID6%
Stevens1%
Benewah, ID0%
Bonner, ID0%
Spokane0%
Whitman0%

Too few tested to show: Lincoln, Pend Oreille.

Nitrate guide

Uranium0 of 24 wells over

None of the 24 wells tested here from 2000 to 2016 were over the EPA limit of 30 µg/L, against about 1 in 7 across Washington. Spokane County had none, while 2 of the 7 other Washington counties with 10 or more tested wells had at least one, leaving out 1 county whose results are likely overstated.

Spokane and its neighbors
Stevens64%
Spokane0%
Whitman0%

* Likely overstated, so we don't rank it.

Too few tested to show: Benewah, ID, Bonner, ID, Kootenai, ID, Lincoln, Pend Oreille.

Uranium guide

Arsenic0 of 24 wells over

None of the 24 wells tested here from 2000 to 2016 were over the EPA limit of 10 µg/L, against about 1 in 7 across Washington. At least half the results were too low for the lab to measure, and the top 1 in 10 were 3.0 µg/L or more. Spokane County had none, while 9 of the 13 other Washington counties with 10 or more tested wells had at least one, leaving out 1 county whose results are likely overstated.

Spokane and its neighbors
Stevens12%
Bonner, ID11%
Kootenai, ID10%
Benewah, ID3%
Spokane0%
Whitman0%

Too few tested to show: Lincoln, Pend Oreille.

Arsenic guide

Lead0 of 24 wells over

None of the 24 wells tested here from 2000 to 2016 were over the EPA action level of 15 µg/L, against about 1 in 37 across Washington. Spokane County had none, while 2 of the 14 other Washington counties with 10 or more tested wells had at least one.

Spokane and its neighbors
Kootenai, ID7%
Stevens6%
Benewah, ID0%
Bonner, ID0%
Spokane0%
Whitman0%

Too few tested to show: Lincoln, Pend Oreille.

Lead guide

Fluoride0 of 24 wells over

None of the 24 wells tested here from 2000 to 2016 were over the EPA limit of 4 mg/L, against under 1 in 100 across Washington. Spokane County had none, while 2 of the 16 other Washington counties with 10 or more tested wells had at least one.

Spokane and its neighbors
Benewah, ID0%
Bonner, ID0%
Kootenai, ID0%
Spokane0%
Stevens0%
Whitman0%

Too few tested to show: Lincoln, Pend Oreille.

Too few Spokane County wells were tested for this one.

Radon in water1 well tested

Only 1 well here was tested in 2016, too few to say how common it is. Across Washington it's about 2 in 10.

Radon guide

None of the 1 Spokane County wells tested for bacteria had it, but every well needs a yearly test.

Coliform bacteria0 of 1 wells had it

None of the 1 wells tested here in 2016 had coliform bacteria, against about 4 in 10 across Washington.

Bacteria guide

E. coli0 of 1 wells had it

None of the 1 wells tested here in 2016 had E. coli, against about 1 in 9 across Washington.

E. coli means human or animal waste is getting in, so if a test of your Spokane County well finds it, boil drinking water until the well is fixed.

Bacteria guide

Iron reached staining levels in 2 of 24 tested wells, and it isn't a health risk.

Iron stains2 of 24 wells had it

2 of 24 wells tested here from 2000 to 2016 had enough iron to stain (0.3 mg/L), against about 2 in 10 across Washington.

Spokane and its neighbors
Stevens41%
Whitman36%
Benewah, ID31%
Kootenai, ID18%
Bonner, ID16%
Spokane8%

Too few tested to show: Lincoln, Pend Oreille.

Iron guide

Most of the 41 wells tested in Spokane County were last tested before 2010.

23 wells had a test in the 2000s and 18 in the 2010s.

An old result shows the water as it was then, so treat these 41 wells as a starting point and test your own.

Most Spokane County wells in these records were tested for research or because someone suspected a problem, which can push the shares above what a typical home well would show (how we read the numbers).

One mail-in lab test covers the 3 things to check in Spokane County.

  • Bacteria
  • Nitrate
  • Arsenic

What Washington offers well owners

Here's what we know about radon and PFAS in Spokane County.

Spokane County is in the EPA's highest radon zone. Radon from well water adds to the radon in your indoor air, so test your air first, and your water too if the air is high. Radon guide

Between 2023 and 2025 the EPA had 24 town water systems in Spokane County test for PFAS. 8 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 12 ng/L of PFOS. No well in Spokane County has public PFAS results, so the town systems are the best clue to what's in the groundwater nearby. PFAS guide

Radon zones: EPA Map of Radon Zones. PFAS: EPA tests of town water systems, 2023 to 2025

Next door to Spokane County
Bonner, IDKootenai, ID
Elsewhere in Washington
YakimaThurstonMasonPierce

All of Washington

Get a yearly reminder to test your Spokane County well

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Questions people ask about well water in Spokane County

Is well water in Spokane County safe to drink?

Most tested wells in Spokane County came in under the limits. Of 6 health checks with enough tests, nitrate came closest, at 0 of 18 wells over. Every well is different, so test yours for bacteria, nitrate and arsenic.

Can I get my well tested for free in Spokane County?

DOH offers free nitrate and coliform testing to eligible well owners in parts of the Lower Yakima Valley and Western Benton County. If not, use a lab Washington has certified for drinking water. Ask for bacteria, nitrate and arsenic, the tests that matter most in Spokane County.

How does Spokane County compare with the counties around it?

For manganese, the share of tested wells over the limit: 4 of the 5 neighboring counties with data had a higher share than Spokane County, at 0%. Stevens had the most, at 39%. Groundwater doesn't stop at county lines, so Stevens's 39% is worth knowing about if you live near it.

How often should I test my well in Spokane County?

None of the 1 wells tested for bacteria in Spokane County had it, but the CDC still says to test for bacteria and nitrate every year, and right away after a flood, a repair, or any change in taste or smell.

By the Tested Water teamData from the USGS, EPA and Department of Health (DOH); Department of Ecology for well records and lab accreditationUpdated November 8, 2026

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Where the Spokane County numbers come from

  • People on wells: 32,762 in Spokane County, from EPA estimates built on the 2020 Census (Murray et al.).
  • Lab tests: 933 well water samples from 41 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2019.
  • Neighboring counties: the 7 counties that share a border with Spokane County, from the Census Bureau's county adjacency file.
  • PFAS: EPA tests of 24 town water systems in Spokane County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
  • Radon: Spokane County is zone 1 on the EPA Map of Radon Zones.
  • State programs and links: Department of Health (DOH); Department of Ecology for well records and lab accreditation, checked November 1, 2026.
Download this county's data (CSV)How we read these numbersReport an error
Test for bacteria and nitrate every yearSee lab tests