Section 58.01.02.251 - SURFACE WATER QUALITY CRITERIA FOR RECREATION USE DESIGNATIONS01.Toxics Criteria. Waters designated for recreation must meet the Fish Only water quality criteria set forth in Subsection 210.01.b.02.Fecal Indicators. Waters designated for recreation must meet criteria for indicator bacteria of fecal contamination. Either of the following indicators is sufficient for determining compliance with the fecal indicator criteria:a.E. Coli Bacteria. i. Waters designated for recreation are not to contain E. coli bacteria, used as indicators of human pathogens, in concentrations exceeding: (1) A geometric mean of one hundred twenty-six (126) E. coli counts per one hundred (100) mL based on a minimum of five (5) samples taken every three (3) to eleven (11) days over a forty-five (45) day period; or(2) A statistical threshold value (STV) of four hundred and ten (410) E. coli counts per one hundred (100) mL in more than ten percent (10%) of samples collected over a forty-five (45) day period. The Department will ensure samples collected represent the forty-five (45) day duration.ii. For public swimming beaches, a single sample value of two hundred thirty-five (235) E. coli counts per one hundred (100) mL should be used in considering beach closures.b. Enterococci. Waters designated for recreation are not to contain enterococci bacteria, used as indicators of human pathogens, in concentrations exceeding: i. A geometric mean of thirty-five (35) enterococci counts per one hundred (100) mL based on a minimum of five (5) samples taken every three (3) to eleven (11) days over a forty-five (45) day period; orii. A statistical threshold value (STV) of one hundred and thirty (130) enterococci counts per one hundred (100) mL in more than ten percent (10%) of samples collected over forty-five (45) day period. The Department will ensure samples collected represent the forty-five (45) day duration.c. For comparing permit effluent bacteria samples to the criteria, the averaging period shall be thirty (30) days or less based on a minimum of five (5) samples.Idaho Admin. Code r. 58.01.02.251