United States
About this guideline ▾
The United States has two sets of federal water quality guidelines. The EPA Aquatic Life Criteria set recommended concentration limits for pollutants to protect aquatic species under the Clean Water Act. The EPA 2012 Recreational Water Quality Criteria provide thresholds to protect human health in freshwater and coastal waters used for swimming and other primary contact recreation.
E. coli
Freshwater
| Range | Level | Impact |
|---|---|---|
| ≤ 126.0 CFU/100 mL | Met guideline | Geomean |
| ≥ 235.0 CFU/100 mL | Exceeds chronic guideline | Beach Action Value |
| ≥ 410.0 CFU/100 mL | Exceeds acute guideline | Single sample maximum |
E. coli is a bacterium found in human and animal waste, and its presence in recreational water signals fecal contamination and potential risk to swimmers. When levels are elevated, swimmers risk gastrointestinal illness and other infections. The U.S. EPA's 2012 Recreational Water Quality Criteria (RWQC) recommend a geometric mean of 126 CFU/100 mL and a statistical threshold value (STV) of 410 CFU/100 mL for freshwater, or a more protective option of 100 CFU/100 mL and 320 CFU/100 mL. The Beach Action Value of 235 CFU/100 mL or more protective 190 CFU/100mL is recommended.
https://www.epa.gov/wqc/recreational-water-quality-criteria-and-methods