Interpreting Bacteria Results
Interpreting results of a total bacteria test:
The detection range of the total bacteria test is 500-10000 CFU/mL. Microbial load is expressed in colony-forming units of bacteria per millilitre of water (CFU/mL) in order to translate the result for comparison to the US Environmental Protection Agency’s (EPA) standards. According to US EPA guidelines, drinking water is required to have less than 500 CFU/mL of total heterotrophic bacteria and no detectable amount of E.coli.
For total microbial load, your results can be interpreted in the following way:
| Range | Interpretation | Treatment Recommendation |
| < 500 CFU/mL | Total microbial load is below the recommended limit and treatment is not required. | Maintain on-going testing and your current treatment plan.Revise your treatment plan if needed to maintain this bacteria level between tests. |
| 500 - 2000 CFU/mL | Total microbial load is moderately low. The issue may be localized or seasonal. Do not drink water from this source until the microbial load is decreased. | The total microbial load is above the recommended limit, but not dangerously. Retest to confirm results and schedule system maintenance as needed. |
| 2000 - 5000 CFU/mL | Total microbial load is moderately high. Biofilm may be developing in the water source. Water from this source is not safely drinkable. | Immediate treatment is required. Test upstream to determine the source of the issue. Replace parts as needed or increase disinfection and retest over time. |
| > 5000 CFU/mL | Total microbial load is high. Biofilm has likely developed and water from this source should not be used for drinking, bathing or swimming. | Immediate aggressive treatment is required. Test points upstream to determine if the issue is widespread. Replace parts as needed or increase disinfection and retest over time. |
For disinfection plan recommendations, see the following help article: https://exactblue.helpscoutdocs.com/article/34-treatment-options-and-recommendations