How to Conduct Radionuclide Testing for Well Completion Interim Approval
TCEQ Plans Review Well Completion Checklist
In order for you to receive interim approval, you must complete each item on the Plans Review Well Completion Checklist (PDF file; help with PDF), including specified chemical testing. For certain counties, you must also conduct radionuclide testing.
Counties for which Radionuclide Testing is Required for Well Completion
Several areas of Texas have elevated radionuclide levels. If you are drilling a well in one of the counties listed in Table 1, you must conduct radionuclide testing for interim approval. 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.
Counties where Radionuclide Testing is Required
|County Name||State Code *|
* The state county code is the first three digits of the PWS ID number
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 uraniums are 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.
|Contaminant (pCi/Liter except *)||Trigger|
|Gross Alpha||Performed on all samples|
|Gross Beta||Performed on all samples|
|Radium-228||Performed on all samples|
|Radium-226||If gross alpha + Ra-228 >5.0 pCi/Liter|
|Combined Uranium*||If gross alpha >15 pCi/Liter; reported in ( g/Liter)|
|Uranium-234||If gross alpha >15 pCi/Liter|
If gross alpha >15 pCi/Liter
|Uranium-238||If gross alpha >15 pCi/Liter|
|Tritium||If gross beta >50 and the system is designated by TCEQ as vulnerable.|
|Radioactive Strontium||If gross beta >50 and the system is designated by TCEQ as vulnerable.|
|Gamma-Emitting Radionuclides||If gross beta >50 and the system is designated by TCEQ as vulnerable.|
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
Acceptable Methods for Radionuclide Testing
Our Compliance Support Division maintains a list of acceptable methods for analyzing for radionuclides in public drinking water. Also be aware that radionuclide analyses take longer to complete, so plan ahead.
Laboratory Information for Radionuclides Only
At this time, public water systems are not required to use a laboratory certified by the TCEQ for public drinking water for the well completion interim approval. This is subject to change. Before using any lab, you must verify that the laboratory can conduct the analyses as required above. Consider these two lists of available labs:
- Labs that are TCEQ-certified for public drinking water. (PDF file. Help with PDF.)