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Guidance for Reporting Total Coliform (TC) Sampling

Currently, some Point of Compliance (POC) wells are reporting positive Total Coliform (TC) results, where there might not be any actual TC contamination. The monitoring limits in the Aquifer Protection Permit (APP) rules are based on the Drinking Water (DW) Standards and the maximum contamination levels (MCLs), which include testing for TC in all aquifer POC wells.  

Some newer APPs issued by ADEQ have footnotes in Section 4.0 (older APPs do not have these footnotes) that allow sampling checks for E. Coli (EC) or Fecal Coliform (FC) to determine if a “positive” TC result is valid, per DW standards. All POC well bacteria samples should be tested for both TC and E. Coli to help determine if there is an exceedance for TC.*

* As of April 2019 the footnote for TC testing was change to EC/FC testing only.

Total Coliform Testing Results Flow Chart

Use this chart to help ensure TC testing results are accurately reported to ADEQ | View Chart >

Guidance Doccument 

Save a PDF version of this guidance document | Download/Print >


ADEQ would like to help your facility remain in compliance with all requirements. If you have questions, please contact the inspector who last visited your facility, or call 602-771-4479 for compliance assistance.