Radon in Pima County Residential Water: What USGS Sampling Shows About Aquifer N100BSNRGB

The U.S. Geological Survey sampled six wells from the N100BSNRGB aquifer area in Pima County between June and September 2013, finding radon-222 concentrations ranging from 175.0 to 1410.0 picocuries per liter (pCi/L), with a median of 1100.0 pCi/L. All samples showed detected radon; none exceeded federal thresholds. This record helps clarify some common beliefs about radon in household water.

Radon Treatment Requires Frequent Equipment Maintenance

Radon treatment systems involve media or filtration components that reduce radon levels from water before household use. The Autotrol Radon in Water Filter system ships ready to configure and typically requires routine maintenance, such as replacing the filtration media or cartridges, on a schedule driven by water usage and radon load. Regular upkeep ensures continued radon reduction but varies based on household water demand and radon concentration levels.

Household Size, Second Homes, and Seasonal Use Affect Treatment Needs

For large households, treatment media may saturate faster, shortening maintenance intervals. In second homes or seasonally occupied properties, radon buildup in the water system during inactivity requires consideration, but the treatment system’s downtime needs are generally manageable by flushing protocols. Adjusting media replacement schedules based on usage patterns optimizes performance.

Understanding 'Detected,' 'Median,' and 'Range' in Radon Sampling

Detection means radon was measurable in all sampled wells within Pima County's aquifer, but it does not imply a specific health risk without further well-specific testing. The median of 1100.0 pCi/L indicates the middle value among those six samples, while the range shows the lowest and highest detected concentrations. These figures describe the aquifer’s general radon presence but do not determine an individual household’s radon concentration.

Sample and Well Depth Influence Expected Radon Levels

The USGS wells sampled ranged from 300 to 800 feet deep. Groundwater radon concentrations often increase with depth because radon originates from natural radioactive decay in soil and rock formations. Shallower wells might show lower radon, but this depends on local geology. Knowing the depth of your water source helps anticipate potential radon levels, but only a direct test of your own water confirms its radon content.

Radon Differs From Other Water Quality Issues Like Hardness or Iron

Radon is a radioactive gas naturally occurring in groundwater, unlike mineral-related issues such as hardness or iron that affect taste and staining. It dissolves in water and can release into indoor air during water use, which is a different exposure route than minerals causing visible water effects. Treatment technologies targeting radon focus on gas removal or decay reduction rather than mineral filtration.

Leaving Radon Untreated Over Time Does Not Produce Immediate Visible Water Changes

Radon presence in water does not affect water color, taste, or odor noticeably. If untreated over many years, radon can contribute to indoor air exposure when water is used for showering, cooking, and cleaning. This gradual exposure differs from immediate aesthetic water problems but is an important factor for residential radon management strategies.

In summary, the USGS data provide a baseline for understanding radon in Pima County’s N100BSNRGB aquifer water but cannot specify household levels. To decide between treatment options, homeowners should test their own water and consider usage patterns and maintenance commitments. The Autotrol Radon in Water Filter system offers a documented water treatment approach ready for residential configuration to help address radon gas dissolved in water.

Where this information comes from

Source: USGS groundwater sampling. Sampled 2013-09-04. 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 N100BSNRGB aquifer (Pima County): 6 results from 6 wells, median 1100.0 pCi/L, range 175.0-1410.0 pCi/L; none above any federal threshold