Most people who think about radon think about basements. They've heard the public health campaigns. They know radon comes from the soil, seeps into the lowest level of the house, and accumulates if there's no ventilation. They've maybe even tested their basement. They feel like they've handled it.
What they haven't thought about is the shower.
Radon in water is a separate problem from radon in soil, and it works differently. When water that contains dissolved radon gas is heated or agitated — when you run the shower, when the dishwasher runs, when you do laundry in hot water — the radon volatilizes. It comes out of the water and into the air. Your bathroom, during and after a hot shower, can have radon concentrations significantly higher than your basement.
You're not drinking the radon. You're breathing it. Every morning.
Why Is Radon in Water Worse in Litchfield County?
Connecticut's radon risk is not uniform. The state sits on a complex geology, and radon concentrations in groundwater track closely with the underlying rock. Granite bedrock — which dominates the Litchfield Hills, the eastern highlands, and parts of the Connecticut River Valley — produces significantly more radon than the sedimentary rock that underlies much of the state's coastal areas.
Litchfield County averages 5.0 pCi/L of radon in indoor air — above the EPA's action level of 4.0 pCi/L. This is an average. Individual wells in the area can run dramatically higher. The CT Department of Public Health's data on groundwater radon shows concentrations ranging from 50 to 500,000 pCi/L in Connecticut's groundwater. The variation is enormous, and it's driven by local geology.
The towns of Litchfield, Bantam, Torrington, Goshen, Sharon, Cornwall, and the surrounding communities sit on some of the most radon-productive geology in the state. If you're on a private well in this area and you've never tested your water for radon, you're making an assumption about your risk that the geology doesn't support.
How Does Radon Get from Well Water into Your Bathroom Air?
Here's the mechanism: radon dissolves readily in cold groundwater. Your well water comes up from the aquifer carrying dissolved radon. When that water hits your hot shower, the temperature change causes the radon to come out of solution — the same way CO2 comes out of a soda when you open the can. The radon becomes airborne in your bathroom.
A typical shower in radon-contaminated well water can raise bathroom air radon levels to 10-20 times the baseline level in the rest of the house. If you take a 10-minute shower in a bathroom with limited ventilation, you're breathing elevated radon for 10 minutes. Every day. For years.
The cumulative exposure adds up. Radon is the leading cause of lung cancer in non-smokers in the United States. The EPA estimates it causes about 21,000 lung cancer deaths per year. The majority of those deaths are attributed to radon in air, but radon in water contributes — particularly in households where the water source is a private well with elevated radon levels.
The Testing Gap
Here's the part that should concern every well owner in Litchfield County: radon is not included in the standard mortgage water test. It's not included in the basic CT DPH well test. It's not something most home inspectors test for unless you specifically request it.
The result is that a significant number of households in high-radon-geology areas are using well water with elevated radon and have no idea. They tested for bacteria and nitrates. They passed. They feel safe.
Testing for radon in water is straightforward and not expensive — typically $25-$75 for the test itself. The sample is collected from a cold water tap (before any treatment), sent to a certified lab, and results come back within a week or two.
If radon is found above the EPA's suggested action level of 300 pCi/L for water, treatment options include aeration systems (which bubble the radon out of the water before it enters the house) and granular activated carbon filters. Aeration is generally preferred for high radon levels because it doesn't accumulate radioactive decay products the way carbon filters can.
The Practical Reality
If you live in Litchfield County, Tolland County, or eastern Connecticut on a private well, and you've never tested your water for radon, add it to the next test. It's a small addition to a comprehensive water test, and the result tells you something important about what you're breathing every morning. The same granite bedrock that produces radon also produces uranium in some eastern Connecticut wells — another contaminant the standard test misses.
Is radon in your water? Enter your ZIP code at CheckYourTap.com to see what's in your tap water — free, in 30 seconds.
The basement test you did three years ago doesn't tell you about the water. They're separate pathways. You need to test both.
And if you do find elevated radon in your water, the fix is real and it works. An aeration system installed at the point of entry — where the water comes into the house — removes the radon before it ever reaches your taps. The shower stops being a problem. The dishwasher stops being a problem. The water is clean.
Keep Reading
- The Water Test You Got When You Bought Your House Is Worthless Now
- There's Uranium in Some Eastern Connecticut Wells. It's Not from a Nuclear Plant.
- You're Pregnant in Connecticut. Here's What to Know About Your Water Before Your Next Glass.
Frequently Asked Questions
Can you get radon exposure from a shower?
Yes. When well water containing dissolved radon is heated in a shower, the radon volatilizes — it comes out of the water and into the air. A typical shower in radon-contaminated well water can raise bathroom air radon levels to 10–20 times the baseline in the rest of the house. In a poorly ventilated bathroom, a 10-minute daily shower means years of elevated radon inhalation. Radon is the leading cause of lung cancer in non-smokers.
How do you test for radon in well water?
Testing is straightforward and costs $25–$75. Collect a water sample from a cold water tap before any treatment, send it to a certified lab, and results come back within one to two weeks. The EPA's suggested action level for radon in water is 300 pCi/L. This is separate from a basement radon test — radon in soil gas and radon in water are different pathways that must be tested independently.
How do you remove radon from well water?
Aeration systems are the preferred treatment for radon in water. These systems bubble the radon out of the water before it enters the house, venting the gas safely outside. Granular activated carbon (GAC) filters can also reduce radon but are less preferred for high levels because they accumulate radioactive decay products. An aeration system installed at the point of entry eliminates radon from all taps, showers, and appliances simultaneously.
Sources: CT DPH Radon in Your Well Water guidance; CTCASE Radon in Connecticut's Drinking Water Supplies study; EPA Radon Zone Map for Connecticut; Litchfield radon data, RadonResources.com; CT DPH radon potential map.