If your kitchen or bathroom fixtures seem most affected by water issues, consider radon's behavior in water systems
Radon is a radioactive gas that naturally dissolves into groundwater in some regions, including Fresno County's aquifer. When water containing radon is used in household fixtures like showers, faucets, or appliances, radon can be released into the air or ingested. Because radon is a gas, the fixtures that aerate water—showers and dishwashers—often show effects first through airborne exposure. This is why radon concerns typically arise around these points of use rather than in cold water taps alone.
If you are looking at public water system records, note how they differ from private well tests
The U.S. Geological Survey sampled groundwater from 36 wells at 100 to 400 feet depth in the Fresno County aquifer between late 2013 and early 2014. Radon-222 was detected in all 41 samples, with a median level of 640 picocuries per liter and a range from 114 to 6700 picocuries per liter. These figures describe radon’s presence across this regional aquifer but do not represent any single private well or household water source. Public water suppliers in this area must comply with federal treatment thresholds, and no sample in this set exceeded any federal limit for radon. Private well owners should recognize that area measurements establish a background but cannot substitute for individual water testing of their own supply.
If you plan to seek treatment advice, document key details about your water and household
Before considering water treatment, write down several details to clarify your water quality and needs. Record results from a certified laboratory radon test of your own household water supply, noting the radon concentration reported. Note which fixtures or appliances exhibit water-related issues or unusual odors. Document your household water usage patterns, including peak flow rates and daily consumption. Include details on your water source type—private well or public system—and whether your water undergoes any current treatment. This information streamlines assessment and aids in determining whether radon-specific treatment fits your situation.
If you choose to address radon in water, understand how the Pentair Radon in Water Filter operates
The Pentair Radon in Water Filter is designed to reduce radon levels in residential water supplies. It uses specialized media technology that adsorbs radon gas as water passes through the filter system. This process lowers radon concentration before the water reaches household fixtures, reducing both ingestion and inhalation risks associated with radon release from water. The filter ships ready to configure and adjusts to typical residential water flow rates. While it does not remove other contaminants, targeting radon specifically can improve safety and peace of mind when radon is detected in your water.
If you compare Fresno County’s radon data with neighboring counties, avoid overinterpreting differences
Radon levels vary naturally due to geology and groundwater conditions. Neighboring counties may show different median and range values from the same USGS sampling program. Comparing these figures offers insight into regional variation but does not predict radon levels in any single household's water. Overreading differences risks misjudging your actual exposure. Federal limits and local regulatory requirements remain the consistent standard rather than relative measurements. Focus on your own testing results and local guidelines for treatment decisions rather than county-to-county comparisons.
Understanding how radon behaves in household water, what government sampling reveals for Fresno County aquifers, and how to document your specific water quality helps you make informed treatment choices. The Pentair Radon in Water Filter provides a targeted solution to reduce radon in residential water once you confirm the need through testing.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2014-04-08. 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 (Fresno County): 41 results from 36 wells, median 640.0 pCi/L, range 114.0-6700.0 pCi/L; none above any federal threshold