S.D. Admin. R. 74:53:01:25

Current through Register Vol. 51, page 64, December 9, 2024

Section 74:53:01:25 - Minimum capacities for septic tanks

The minimum capacities for septic tanks serving individual or small on-site systems shall be determined as follows:

(1) All septic tanks receiving wastewater flows of 750 gallons per day or less shall have a minimum capacity of at least 1,000 gallons of liquid before there will be an overflow into the septic tank outlet. When a housing unit or units served by a septic tank contains more than three bedrooms, each bedroom in excess of three shall require an additional 250-gallon increase in the capacity of the septic tank beyond the 1,000 gallons. If a septic tank receives wastes from a garbage disposal, the overall capacity of the tank shall be increased by an additional 20 percent;

(2) Septic tanks serving premises other than housing units or receiving wastewater flows of more than 750 gallons per day but equal to or less than 1,500 gallons per day shall have a minimum liquid volume capacity to permit retention of incoming sewage at 150 percent of the average daily flow;

(3) Septic tanks receiving wastewater flows greater than 1,500 gallons per day shall have a minimum liquid volume capacity (V) equal to at least 1,125 gallons plus 75 percent of the daily wastewater flow (Q), or V = 1,125 + 0.75Q; and

(4) Septic tanks serving premises where high amounts of oil or grease are anticipated shall be preceded by grease interceptors. Wastewater from garbage disposals may not be discharged to grease interceptors. Grease interceptors shall have a grease retention capacity of not less than 2 pounds for each gallon per minute of flow. The minimum size of grease interceptors shall be 750 gallons. Construction and installation of interceptors shall meet the requirements of chapter 20:54:06 of the South Dakota state plumbing code.

S.D. Admin. R. 74:53:01:25

12 SDR 2, effective 7/18/1985; 13 SDR 129, 13 SDR 141, effective 7/1/1987; transferred from

General Authority: SDCL 34A-2-93.

Law Implemented: SDCL 34A-2-20.