Every time you run the shower, wash dishes, or start the dishwasher, a well drawing from the wrong rock can release a radioactive gas into your air. You won’t smell it. You won’t see it. Radon in well water is one of the few contaminants around Wenatchee that can hurt you through your lungs, not just through your glass of drinking water, and most homeowners have never ordered the test.
That’s the surprising part. Nitrates, arsenic, and iron get talked about at every closing table in the valley. Radon almost never comes up, even though parts of Chelan and Douglas County sit on granite bedrock known to run higher in radon than the basalt flats down toward Quincy and Moses Lake. If you’ve never tested, you’re not alone, and you’re not necessarily in danger either. It’s just worth twenty minutes to understand what you’re dealing with.
If you already know your well sits on granite ground near Leavenworth, Plain, or the upper Wenatchee River valley, don’t wait to read the rest of this before you get a water test scheduled. We’ll walk you through what the result actually means once it lands in your inbox.
What Radon in Well Water Actually Is
Radon is a naturally occurring radioactive gas that forms when uranium in rock and soil breaks down over time. It’s invisible, odorless, and tasteless, which puts it in the same “you’d never know” category as arsenic and nitrates. The difference is where it comes from and how it reaches you.
Uranium shows up in trace amounts in nearly all rock, but granite holds more of it than basalt. That matters here because North Central Washington sits at the boundary between two very different geologies. The Cascade foothills around Leavenworth, Plain, and parts of the upper valley are built on granite and granodiorite, while the Columbia Plateau stretching toward Quincy and Moses Lake is mostly basalt, which tends to produce less radon.
Wells drilled into fractured granite, or into gravel and sand aquifers fed by groundwater that has moved through granite, are the ones most likely to pick up dissolved radon gas. That’s a general pattern, not a rule that applies to every well in Leavenworth and skips every well in Quincy. The only way to know where your specific well falls is to test it.
Two Ways Radon Reaches You: Breathing It vs. Drinking It
This is the part that surprises most people. Radon in well water isn’t mainly a drinking problem. It’s mainly a breathing problem.
When radon-laced water comes out of a faucet, showerhead, or washing machine, the gas releases into the air of your home. Hot water and agitation, like a hot shower, release it fastest. The EPA’s radon program notes that inhaling radon released from water is a far bigger lifetime cancer risk than swallowing it in a glass of water, since radon is linked to lung cancer, not stomach or bladder issues the way arsenic is.
Radon is the second leading cause of lung cancer in the United States after smoking, and most of that risk nationally comes from radon seeping into homes through soil and foundations, not from well water. Water is usually a secondary contributor. In a home with a strong well-water source and a lot of showering and laundry, it can still meaningfully raise indoor air levels.
That’s also why radon in well water and radon in your home’s air are two separate tests. A soil-gas radon problem coming through your foundation has nothing to do with your well, and a high water reading doesn’t always mean your indoor air is elevated too. Careful homeowners test both.
Is There a Safe Radon in Well Water Level?
Here’s where radon gets messier than arsenic or nitrates. The EPA has never finalized a nationwide legal limit for radon in drinking water, though it has proposed standards over the years, generally in the range of 300 picocuries per liter (pCi/L), with a higher allowance of 4,000 pCi/L for water systems that also run an active program to address radon in indoor air.
Washington doesn’t regulate radon in private well water either, though the Washington State Department of Health publishes general guidance for well owners who want to test. That leaves you working from guidance rather than a hard legal cutoff:
- Under 300 pCi/L: Generally considered lower risk from the water itself, though it’s still worth checking your home’s indoor air separately.
- 300 to 4,000 pCi/L: A gray zone. Many water treatment professionals recommend addressing it, especially if your indoor air radon is also elevated.
- Above 4,000 pCi/L: Most labs and health agencies recommend treatment regardless of your indoor air results.
For comparison, indoor air radon is measured in picocuries per liter of air, and the EPA’s action level there is 4 pCi/L, a completely different scale than the water numbers above. Don’t mix up the two units when you’re reading a lab report.
Priya and Dave in Leavenworth ran into that confusion firsthand. They’d tested their home’s indoor air two years earlier after an inspector’s canister test came back at 5.2 pCi/L, just over the EPA action level, and they’d installed a soil depressurization system to fix it. What they hadn’t done was test their well water. When they finally did, mostly out of curiosity, their water came back at 6,800 pCi/L, well into the range where treatment is typically recommended. The two problems turned out to be connected, since their granite-country well was likely feeding radon into the air on top of the soil gas they’d already dealt with.
How to Test for Radon in Well Water
Testing radon in well water takes a specific kind of lab test, not a strip you dip in a glass.
- Order a certified water radon test. A Washington-accredited lab can supply a sample kit for $50 to $150 as a standalone test, or bundled into a broader private well panel for $150 to $400.
- Sample from an untreated cold tap, the same rule as every other well test. You want to know what’s coming out of the ground, not what a softener or filter is already catching.
- Handle the sample fast. Radon has a short half-life, about 3.8 days, so labs want the sample shipped and tested quickly. Follow the kit’s timing instructions exactly or your result can read artificially low.
- Test your indoor air separately. A short-term charcoal canister test for indoor air runs $15 to $30 and takes 2 to 7 days. It’s a different test from the water sample and measures a different exposure.
If you’re buying or selling a home on well water anywhere from Cashmere to Chelan, get this done before closing, not after. Our guide to well inspections when buying a home covers the rest of the pre-purchase checklist, and our broader rundown on well water testing in Wenatchee walks through which panels to order and when.
Not sure whether your property sits on higher-risk granite ground or safer basalt ground? Call us at (509) 351-8404 and we can talk through your well’s location and depth before you spend a dime on testing.
Treatment Options for Radon in Well Water
If your well tests high, you have two proven ways to treat it, and one popular option that’s a poor fit for most homes.
Aeration systems are the gold standard for radon in well water. These whole-house units spray incoming water into a tank and vent the released gas safely outside through a fan and pipe, essentially doing on purpose, and before the water reaches your tap, what happens naturally when you shower. Aeration removes 95 to 99.9 percent of radon and doesn’t build up radioactivity in a filter media, which is why most water treatment professionals recommend it first.
Granular activated carbon (GAC) tanks can also remove radon and sometimes cost less to install. The catch is that radon decays into other radioactive particles that accumulate on the carbon media over time. On a high-radon well, that can turn the tank itself into a low-level radioactive source, usually requiring extra shielding, installation away from where people spend time, and periodic monitoring. Most pros steer higher-radon households toward aeration instead.
What doesn’t work: standard sediment filters, water softeners, and UV disinfection. None of them touch dissolved gas, so don’t expect equipment bought for iron, hardness, or bacteria to do anything for radon.
Aeration systems involve electrical fan wiring, venting that has to be routed correctly so radon doesn’t get pulled back into the house, and plumbing tied into your main water line. That combination of electrical work and pressurized plumbing is not a weekend DIY project. If a job touches your wellhead, casing, downhole equipment, or main electrical panel, that’s a call for a licensed professional every time.
| Item | Typical cost | Notes |
|---|---|---|
| Water radon test (standalone) | $50 - $150 | Certified lab, mail-in sample |
| Full private well panel (radon plus bacteria, nitrates, arsenic, etc.) | $150 - $400 | Best value if you’ve never tested |
| Indoor air radon test (short-term canister) | $15 - $30 | Separate from water; measures a different exposure |
| Whole-house aeration system, installed | $2,500 - $3,500 | Upper end of typical treatment system pricing for our area |
| GAC tank system, installed | $800 - $2,000 | Lower upfront cost, with a radioactive buildup tradeoff on high-radon wells |
| Annual system check and retest | $100 - $200 | Fan, tank, and water retest combined |
Tom in Cashmere is a good example of the low-cost outcome. His property sits on the valley floor, well outside granite country, but he wanted peace of mind after a neighbor’s radon scare made the rounds. His full water panel, radon included, cost $220 total, and it came back under 200 pCi/L. No treatment needed, and he’s got a baseline on file if anything ever changes.
Sarah’s story in Chelan went differently. She was under contract on a lake-view property with an older well, and her inspector flagged that the home sat near known granite outcrops. Her water test came back at 5,400 pCi/L. Rather than walk away from the deal, she negotiated a $2,500 credit at closing and used it to install an aeration system with a little left over. Her retest came back under 100 pCi/L within a week of the install.
While a technician is already at your property running water tests or installing treatment, it’s a smart time to have your whole well system checked. Aging pumps and worn pressure tanks often get caught during the same visit instead of turning into a surprise emergency call later. Our team handles well pump repair throughout Wenatchee and pressure tank replacement in Wenatchee, and we can fold a water quality check into either visit. If your treatment technician also spots signs your well pump is failing, get that looked at by someone licensed rather than layering more DIY work on top of a radon system.
What to Do This Week
Keep it simple:
- Find out if your property sits on granite ground, particularly anywhere from Leavenworth up through Plain and the upper valley. If you’re not sure, ask us or check your county assessor’s parcel history.
- Order a radon water test, standalone or as part of a full well panel. Budget $50 to $400 depending on which you choose.
- Order a separate short-term indoor air radon canister test. It’s cheap and answers a different question than the water test does.
- Under 300 pCi/L in water: low priority, retest in a few years.
- Over 300 pCi/L, especially if your indoor air is also elevated: get quotes on aeration treatment.
- Whatever your results, keep the paperwork. Future buyers, insurers, and your own peace of mind will thank you.
Radon isn’t something to panic over, but it’s also not something to guess about. If you want help reading a lab report, deciding between aeration and GAC, or just want a straight answer about whether your part of the valley runs higher in radon, reach out for a free estimate. We’re licensed and insured in Washington, and we test and treat wells from Leavenworth granite country down to the basalt flats near Moses Lake.
Frequently Asked Questions
Is radon in well water actually dangerous?
Yes, particularly through inhalation rather than drinking. When radon-laced water is used for showers, laundry, and dishwashing, the gas releases into your indoor air, and breathing it over years raises lung cancer risk. The risk from swallowing radon in drinking water is much smaller than the risk from breathing it once it’s released into your home’s air.
How is radon in well water different from radon in my home’s air?
They’re related but separate problems with separate causes and separate tests. Air radon usually comes from soil gas seeping through your foundation, while water radon comes from dissolved gas in groundwater that releases when you run the tap. A home can have one problem without the other, so testing both gives you the full picture.
Which parts of the Wenatchee area are most likely to have radon in well water?
Wells drilled into granite or granodiorite bedrock, common in the Cascade foothills around Leavenworth, Plain, and parts of the upper valley, tend to run higher than wells on the basalt-dominated Columbia Plateau toward Quincy and Moses Lake. That’s a general pattern, not a guarantee, since radon can vary well to well even on similar ground. Testing your specific well is the only way to know for sure.
Can I remove radon with a standard whole-house filter or softener?
No. Standard sediment filters and water softeners are built to catch particles and swap hardness minerals, and neither one touches dissolved gas. Removing radon from well water requires an aeration system, or in some cases a granular activated carbon tank, both of which are purpose-built for the job and should be installed by a licensed water treatment professional.