Name: Cheyenne Radon Mitigation
Telephone: (307) 317-5825

Inside Cheyenne city limits, most homes draw water from the city's utility system. Outside it, in the Ranchettes, along the county roads toward Burns, Carpenter, and Pine Bluffs, and on acreage south and west of town, plenty of homes rely on private wells. Groundwater moving through uranium-bearing rock and sediment can pick up dissolved radon, so well owners in Laramie County have one more thing to check.

How radon gets from a well into the air

Radon dissolves in groundwater. When that water is agitated or heated, during showers, laundry, dishwashing, or running taps, some of the radon escapes into the air of the house. So radon in water mostly matters because of what it adds to the indoor air you breathe. Drinking it is a smaller part of the risk.

The EPA's rough rule of thumb is that every 10,000 pCi/L of radon in water adds about 1 pCi/L to indoor air. That means water usually isn't the main source; soil gas through the foundation is. But in homes with high-radon well water, the water can add a meaningful share, especially in bathrooms and laundry rooms.

Is there a standard for radon in water?

Not a binding one for private wells. Federal drinking-water rules apply to public systems, and the EPA proposed but never finalized a radon standard for them. The proposal included a 300 pCi/L limit, or 4,000 pCi/L for systems in states with indoor-air radon programs. Private well owners are responsible for their own testing. Many professionals use the proposed levels as reference points when interpreting results, and they look at water and air together.

Testing a well for radon

Water testing differs from air testing:

Sampling. Water is collected carefully from a tap, ideally before any treatment equipment, without aerating it, and sealed in a vial with no air bubbles. Radon escapes easily, so technique matters.
Speed. Radon decays quickly, with a half-life of about 3.8 days, so the sample has to reach the lab fast, usually within a day or two.
Lab analysis. A certified lab measures the radon concentration in pCi/L of water.

Certified radon professionals can collect the sample, or some labs supply kits with detailed instructions. While you're testing, it's smart to check the well for uranium and other contaminants too, since they often come from the same geology. The Wyoming Department of Environmental Quality and private labs can advise on broader well testing.

Questions about a reading? A certified Cheyenne-area pro can help. (307) 317-5825

Always test the air too

If you're on a well, test both. The air test tells you your total indoor exposure from soil and water combined. The water test tells you how much the well contributes. A home can have high air radon and low water radon, the reverse, or both, and each calls for a different fix.

Treatment options for well water

Aeration systems

Aeration is the most effective approach for high radon in water. The water is agitated or sprayed in a tank so radon is released and vented outside, usually above the roof, before the water goes to the house. Aeration systems typically remove the large majority of the radon and handle high concentrations, but they cost more and need a re-pressurizing pump and electricity.

Granular activated carbon (GAC)

A GAC tank traps radon as water flows through. It's cheaper and simpler, and works for lower concentrations. The drawbacks: the carbon itself becomes mildly radioactive over time as radon decay products build up, which can matter for tank placement and eventual disposal, and effectiveness declines at high concentrations. Professionals generally steer higher levels toward aeration.

Point-of-use filters

Under-sink filters only treat drinking water. Because the main radon risk from water is inhalation during showers and other household use, point-of-entry treatment, meaning the whole house, is the usual recommendation.

Combining air and water fixes

In rural Laramie County, it's common for a home on a well to also need a sub-slab or crawl space system for soil gas. A single certified professional, or two working together, can plan both. Fix the bigger source first, which is usually the soil gas, then retest air and water to see whether water treatment is still needed.

Cost context

Water treatment pricing varies widely with water chemistry, flow rate, and radon level, and we don't have a reliable published average to share. Ask for a written quote that includes installation, electrical work, and maintenance such as carbon replacement or aerator cleaning. For the air side, Angi's 2026 national data puts typical active soil depressurization systems at about $805 to $1,326. That's a national benchmark only.

Questions about a reading? A certified Cheyenne-area pro can help. (307) 317-5825

Questions for a water treatment pro

Will you collect the water sample, and which certified lab analyzes it?
Based on my result, do you recommend aeration or GAC, and why?
Where does the vent from an aeration system discharge?
What maintenance does the system need, and how much does it cost each year?
How will we verify the result after installation?

Laramie County wells: what to know first

Rural homes around Cheyenne draw water from a range of aquifers, from shallow wells to deep wells in the High Plains sediments east of the Laramie Range. Radon levels in well water depend on the rock and sediment the water moves through and how long it stays there, so neighboring wells can differ. A water test is the only way to know your well's level.

Well water questions

Should I test the water or the air first?

Test the air first, since it reflects your total exposure. Then, if you're on a private well, test the water to learn how much the well contributes.

Does boiling or letting water sit remove radon?

Letting water sit or heating it releases radon into the air, which just moves it into your house. That's why whole-house treatment is the usual recommendation.

How often should I retest a treated well?

Follow the installer's maintenance schedule, and retest the water after installation and periodically afterward to make sure the treatment is still working.

Radon in Well Water around Cheyenne