This week you're deciding what level of radon water treatment your household needs. Understanding radon's presence in Sonoma County groundwater and how it might affect your home's water is key to making the right choice.
If you leave radon untreated in your water for years
Radon is a naturally occurring radioactive gas that can dissolve into groundwater from surrounding rocks and soil. In Sonoma County’s aquifer, government sampling shows radon-222 detected consistently across many wells, with concentrations varying widely. Over time, radon in water can release to indoor air during everyday activities like showering and cooking. While radon in water contributes less to indoor air radon levels than soil gas does, prolonged exposure indoors elevates overall radon exposure. Untreated water sources with measurable radon may steadily add to household radon levels, potentially affecting long-term indoor air quality. Deciding on treatment is about managing this added source, not about addressing an acute water safety failure.
If you want to understand your water's radon level accurately
Start with simple plumbing checks to rule out obvious sources of indoor radon unrelated to water, such as soil gas intrusion. Next, review any existing public water system radon data in your area and talk to neighbors with shared wells. However, the only way to know your home's radon concentration in water is to have your well water tested by a certified laboratory specializing in radionuclides. Lab results will provide radon levels specific to your well that government area sampling cannot replace. This step is essential before choosing a treatment system class.
If you compare Sonoma County's radon data to nearby counties
U.S. Geological Survey data for Sonoma County's aquifer shows radon-222 detections in 47 samples from 42 wells ranging from 22 to 755 feet deep, collected in 2012. The median radon concentration was 520 pCi/L, with a range from 10 to 16,700 pCi/L. None of these results exceeded federal radon thresholds. A neighboring county might show different median or range values due to geology or sampling depth, but differences do not directly indicate better or worse well water in your home. Use regional data only as background context, not as a substitute for your own well test.
If you prepare information before consulting on radon water treatment
Write down your well depth and construction details, your household water use patterns, and any radon lab test results if available. Also, note any indoor air radon measurements if performed. Having this information ready will make discussions about treatment options more productive and focused on your household’s needs.
If you observe household water or indoor air symptoms
Visible or taste changes in water are not reliable indicators of radon presence. Radon is odorless and tasteless. Symptoms like periodic headaches or respiratory irritation are more likely from other sources but could be related to elevated indoor radon air levels. Only a proper air or water radon test can clarify this. High indoor air radon without a corresponding water radon source often points to soil gas entry.
Interpreting Sonoma County's radon water data as a homeowner
Consider the median radon of 520 pCi/L measured in the area's groundwater wells as a general reference point, not a precise value for your well. The wide range up to 16,700 pCi/L shows radon concentrations can vary greatly even within the same aquifer. Your household’s radon level might fall anywhere within this range or outside it. This underscores the importance of your own water testing before choosing the level of treatment you require.
To resolve uncertainty, order a water radon test from a certified laboratory capable of testing for radon-222 in residential water. A result aligned with documented federal guidelines will clarify the extent of treatment needed. If treatment is warranted, the Autotrol Radon in Water Filter ships ready to configure and can be selected according to the radon concentration established by your test, helping you address radon in your home’s water supply effectively.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2012-08-23. These figures describe groundwater sampled in this area. They are not a test of any individual private well - only a test of that well can establish its own water.
On record: U.S. Geological Survey sampling of Radon-222 in the aquifer (Sonoma County): 47 results from 42 wells, median 520.0 pCi/L, range -10.0-16700.0 pCi/L; none above any federal threshold