Radon in Well Water: A Guide for York County Homeowners

Radon in well water is radon gas that dissolves into groundwater as it moves through uranium-bearing rock. If you live in York County and your home uses a private well, you should test the water for radon at least once, as the first step in removing radon from well water. Test sooner if your indoor air radon is high. No agency tests private wells for you.

How radon gets into well water

Radon is a colorless, odorless radioactive gas. It forms as uranium breaks down in soil and rock. Most people think of it as a basement problem, because the gas seeps up through the ground and into a home through cracks and gaps in the foundation.

Groundwater picks up radon the same way. As water sits in cracks in bedrock, radon from the surrounding rock dissolves into it. A drilled well pulls that water straight from the rock, often before the gas has a chance to escape. That is why private wells tend to carry more radon than surface water like rivers and reservoirs, where the gas has time to bubble off into the open air.

Public water systems in the York area that draw from surface water are less likely to have high radon. Homes on private wells are the ones to watch.

Why York County well owners should pay attention

York County is in EPA Radon Zone 1, the group of counties with the highest potential for indoor radon. The geology that drives high air readings in local basements is the same geology your well draws from.

Pennsylvania data backs this up. Penn State Extension cites a study of about 900 Pennsylvania wells in which 78% were above 300 pCi/L, 52% were above 1,000 pCi/L and 10% were above 5,000 pCi/L. Those are statewide figures, not York-only numbers, but they show that radon in well water is common here.

There is also no rule that forces anyone to check. Private wells are not covered by the federal Safe Drinking Water Act, and PA DEP notes that private wells are not regulated under that law. If you own the well, testing is up to you.

Should I test my well water for radon in York County?

Yes. If your home is on a private well, test the water for radon at least once. Here is when it matters most:

• Your indoor air radon is high. Water can add to air radon. If your air test came back above 4.0 pCi/L, a water test helps you see how much of that comes from the well.
• Your air system is not getting the numbers down. If a sub-slab system is working but your air level is still higher than expected, the well may be part of the reason.
• You are buying or selling a home. A water radon result answers a question some buyers raise and helps avoid surprises at closing.
• You have never tested. One test gives you a baseline. Unlike air radon, water radon does not swing much with the seasons, so one good sample tells you a lot.

A water test is not expensive. PA DEP's fact sheet lists lab tests at about $25 to $50, though prices vary by lab. The key is collecting the sample correctly, because radon escapes from water fast.

How much does well water add to indoor air?

A common rule of thumb, repeated by PA DEP, is that every 10,000 pCi/L of radon in water adds about 1 pCi/L of radon to the air in your home. The radon escapes when water is sprayed, heated or stirred, such as in a shower, dishwasher or washing machine.

That ratio puts things in perspective:

The exact effect depends on how much water your family uses, the size of your home and how well it is ventilated. Air near a running shower can spike well above the house average for a short time.

For most homes, soil gas under the foundation is the bigger source of indoor radon. That is why we always look at air and water results together before recommending treatment.

What level is a concern?

There is no enforceable radon limit for private wells. In 1999, EPA proposed a 300 pCi/L limit for public water systems, with a higher 4,000 pCi/L alternative for places running indoor air radon programs. That rule was never finalized. To learn how those numbers are used today, read our guide on what level of radon in water is too high.

In practice, many homeowners consider treatment once water levels reach the thousands of pCi/L, and especially when indoor air is also high.

What you can do about radon in well water

If your water result is high, the gas can be removed where water enters the house, before it reaches your faucets and showers. There are two main methods:

• Aeration. The system mixes air into the water and vents the released radon outside. Penn State Extension calls aeration the best available technology for radon in water, with removal rates up to 99.9%.
• Granular activated carbon (GAC). Water flows through a tank of carbon that traps radon. It costs less up front and suits lower levels, but radioactivity builds up in the carbon over time.

A point-of-use filter at one kitchen sink does not solve the problem, because most of the risk comes from radon released into the air from showers, laundry and other household water use. Treatment has to cover all the water entering the home.

Before choosing a system, confirm your result with a properly collected sample and compare it with your indoor air test. The PA DEP Radon Division and the EPA radon page both have background on radon in homes.

Key takeaways

• Radon dissolves into groundwater from rock, so private wells carry more radon than surface water.
• York County is in EPA Radon Zone 1, and Pennsylvania well studies show high water radon is common.
• Private wells are not regulated, so testing is your responsibility.
• About 10,000 pCi/L in water adds roughly 1 pCi/L to indoor air.
• Treat at the point of entry, usually with aeration for higher levels.

Frequently Asked Questions

Does a home inspection include a well water radon test?

Not usually. Most standard home inspections cover air radon only if you ask for it. Water radon is a separate lab test you need to request.

Can I boil water to remove radon?

Boiling releases radon into your kitchen air, which is the exposure you are trying to avoid. It is not a practical fix for a whole house.

Does a water softener remove radon?

No. A standard water softener is not designed to remove radon. You need an aeration unit or a carbon system sized for radon.

Talk to a local team

Have a water radon result and not sure what it means for your home? Call (717) 356-3035 any time for a same-day callback and a free written quote. We review both your water and air numbers before we recommend anything.