Well Water in San Saba County: The Hickory Aquifer's Radium Problem

An old district, a genuinely different aquifer

Most of San Saba County lies within the Hickory Underground Water Conservation District No. 1, created by an order of the Texas Water Commission on June 9, 1982 -- one of the older groundwater districts in the state -- covering all of Mason County and most of McCulloch and San Saba Counties, with smaller portions reaching into Concho, Menard, and Kimble Counties. The district's founding purpose, as with most Texas GCDs, is to conserve, protect, and prevent waste of the groundwater within its boundaries under Chapter 36 of the Texas Water Code. What sets this particular district apart from most others in rural Texas isn't its regulatory structure -- it's the specific chemistry of the aquifer it manages.

The Hickory Sandstone Aquifer is a genuinely important water source across a wide swath of Central Texas -- Mason, Concho, McCulloch, San Saba, Menard, Kimble, and Gillespie Counties all rely on it to varying degrees -- but it also carries naturally occurring radioactive material (NORM) embedded in its host rock: radium-226, radium-228, gross alpha emitters, and radon, the decay product of radium. This isn't contamination from an industrial source; it's a geologic characteristic of the sandstone formation itself, and it shows up in a meaningful share of wells across the aquifer's footprint.

A documented, decades-old regulatory response

This is not a newly discovered or speculative issue. The radionuclide content of the Hickory Aquifer has been studied and addressed by regional water planners for decades: the Hickory Underground Water Conservation District commissioned a Regional Water Supply Plan specifically to mitigate radionuclide levels for Concho, McCulloch, and San Saba Counties, with that study completed back in September 1991. The Texas Water Development Board has published multiple technical reports on the aquifer's hydrogeology and its relationship to local surface features going back even further, and the issue remains part of current regional groundwater planning discussions in Groundwater Management Area 7, which covers the broader Llano Uplift region including San Saba County.

• Radium-226 and radium-228 are regulated together under the federal combined-radium drinking-water standard (5 picocuries per liter) that applies to public water systems; a private well is not legally required to meet that standard, but the same health rationale applies to anyone drinking from an affected well long-term.
• Gross alpha emitters (excluding radon and uranium) are separately regulated for public systems at 15 picocuries per liter.
• Radon itself is a gas that can also pose an inhalation risk from indoor water use (showers, humidifiers), separate from the ingestion risk of radium in drinking water.

What this means for a specific well

Because this is a geologic characteristic of the formation rather than a site-specific contamination event, the practical takeaway for a buyer or existing well owner in San Saba County is straightforward: test before you rely on the water, don't assume a neighboring well's results apply to yours, and know the aquifer's history going in. Radionuclide levels can vary meaningfully well to well depending on depth, specific formation contact, and local geology within the Hickory -- a nearby well testing clean doesn't guarantee a new well on an adjacent tract will. A state-certified laboratory can test for combined radium, gross alpha, and radon; the Hickory Underground Water Conservation District and the Texas Water Development Board are both reasonable starting points for what monitoring data already exists near a specific parcel.

If a test does come back elevated, standard treatment options used for radium in well water generally include ion-exchange (water softening) systems and reverse osmosis, both of which have documented effectiveness in reducing radium concentrations; distillation is another option for radium specifically. None of these are San Saba-specific technologies -- they're the standard toolkit used anywhere radium shows up in groundwater -- but knowing to test for this specific issue, rather than treating it as a generic 'get your well water tested' afterthought, is the local knowledge that matters here. A well driller or hydrogeologist familiar with the Hickory Aquifer locally can also advise on whether a different completion depth within the formation might reduce exposure on a specific parcel.

Before drilling or closing on a property with an existing well in San Saba County, ask the Hickory Underground Water Conservation District directly about any monitoring data for wells near the specific parcel, confirm current well-permitting requirements (the district, not just TCEQ's statewide framework, governs spacing and production here), and budget for radionuclide testing as a standard, not optional, step -- distinct from the routine bacteria/nitrate testing recommended for any private well nationwide.