Unless required to meet instream water quality standards or federal requirements established under the federal Clean Water Act, the board may not establish, under Section 19-5-104, effluent limitation standards for Biochemical Oxygen Demand (BOD), Total Suspended Solids (SS), Bacteria, and pH for domestic or municipal sewage that are more stringent than the following:

(1)	Biochemical Oxygen Demand (BOD): The arithmetic mean of BOD values determined on effluent samples collected during any 30-day period may not exceed 25 mg/l, nor shall the arithmetic mean exceed 35 mg/l during any seven-day period.

(2)	Total Suspended Solids (SS): The arithmetic mean of SS values determined on effluent samples collected during any 30-day period may not exceed 25 mg/l, nor shall the arithmetic mean exceed 35 mg/l during any seven-day period.

(3)

Bacteria: (a)  The geometric mean of total coliforms and fecal coliform bacteria in effluent samples collected during any 30-day period may not exceed either 2000/100 ml for total coliforms or 200/100 ml for fecal coliforms. The geometric mean during any seven-day period may not exceed 2500/100 ml for total coliforms or 250/100 for fecal coliforms. (b)  The geometric mean of E. coli bacteria in effluent samples collected during any 30-day period shall not exceed 126 per 100 mL nor shall the geometric mean exceed 158 per 100 mL respectively during any 7-day period.

(4)	pH: The pH level shall be maintained at a level not less than 6.5 or greater than 9.0.

Amended by Chapter 256, 2020 General Session