Radionuclide Testing for Approval of Well Completion

Radionuclide Testing to Secure Approval for Use of Proposed Wells

Required testing, required checklists, and other guidance for submitting well completion data in order to secure approval to use the well.

Well Completion Checklist for Plan Review

In order to receive approval to use your public water system well, you must submit each item on the  Public Well Completion Data Checklist for Approval to Use (Step 2), including specified chemical testing. For certain counties, you must also conduct radionuclide testing.

Radionuclide Testing is Required for Wells in These Counties

Several areas of Texas have elevated radionuclide levels. If you construct a well in one of the counties listed in Table 1, you must conduct radionuclide testing for all public water system types. This list was prepared from compliance data for existing water systems. Counties listed here have had samples exceeding the maximum contaminant levels for gross alpha and/or combined radium-226 and radium-228.

Table 1: Counties where Radionuclide Testing is Required

Compliance-Related Information to Consider

Before you consider methods and laboratories, you must consider the information listed in Table 2. The laboratory you use must be able to conduct analyses for gross alpha, gross beta and radium-228.

• For gross alpha and radium-228, if the levels of these contaminants exceed the "trigger" conditions below, the laboratory must be able to perform the additional testing listed for radium-226, combined uranium, and the uranium isotopes 234, 235, 238.
• For gross beta, if the levels exceed the "trigger" conditions below (not common), the laboratory must perform tritium, radioactive strontium and gamma emitters.

In other words, when you review your radiological data and the report has gross alpha over 15 pCi/L and uranium is not reported, you will have to resample or reanalyze and resubmit complete results. If you see gross alpha plus radium-228 over 5 pCi/L, and don't have radium-226, you will have to resample or reanalyze and resubmit complete results.

Table 2: Triggers for Additional Radionuclide Testing

You must calculate radionuclide compliance for gross alpha and Combined radium-226 and radium-228 from analytical results if the laboratory does not. Non-detections are calculated as a zero ("<" sign in front of a result). See below:

Compliance Calculations from Radionuclide Analytical Results

• Gross alpha (pCi/L): gross alpha result - uranium-234 result - uranium-238 result - uranium-235 result = compliance level (Maximum Contaminant Level is 15 pCi/L)
• Combined radium (pCi/L): radium-226 result + radium-228 result = compliance level (MCL is 5 pCi/L)
• Combined Uranium (MCL is 30 µg/L): no calculation

Laboratory Information for Radionuclides

Public water systems are required to use a laboratory accredited for drinking water in order to secure approval for a well completion data submittal.

The EPA maintains a list of approved methods of analysis for radionuclides . Please note that analysis for radionuclides takes longer to complete than other constituents, so it is best to plan ahead. Before using any laboratory, you must verify that the laboratory is accredited to conduct the required analyses.

• NELAP-accredited laboratories for public drinking water