(A) A septic tank shall be provided for water-carriage sewage disposal where no public sewer is available. The septic tank shall be constructed with watertight walls and bottom, with inlet baffled or submerged for a depth of 12 to 18 inches and outlet baffled or submerged to a depth of at least 18 inches below the surface of liquid in the tank but not more than half the liquid depth. Baffles shall extend 6 inches above the liquid level. The outlet invert shall be 3 inches lower than the inlet invert. With a 2 compartment tank there shall be adequate connections at mid-depth, and 2/3 or more of the required capacity shall be in the first compartment. A septic tank shall have a removable cover, or manhole, so as to provide access to the tank for purposes of inspection and cleaning. At least 2 manholes shall be provided for a tank more than 10 feet long and at least one manhole per compartment. If a manhole is not located over the inlet, an inspection opening shall be provided at that point. No septic tank shall have a liquid capacity of less than 750 gallons below the outlet invert. The minimum liquid depth of septic tanks shall be 36 inches, measured from the bottom of the invert to the outlet. There shall be a minimum of 8 inches between the liquid level and the underside of the tank cover.
(B) The minimum liquid capacities are as follows:
(1) Two bedrooms, 750 gallons;
(2) Three bedrooms, 900 gallons;
(3) Four bedrooms, 1,200 gallons;
(4) Larger sizes, add 250 gallons per bedroom.
(5) Where additional capacity is needed, 2 tanks may be used in series for one installation. No more than 2 tanks shall be installed in series but larger tanks shall be used to make up the required capacity.
(C) If a garbage disposal system is used in connection with a septic tank, 50% more liquid volume shall be required for the septic tank.
(D) Sink drainage or laundry water systems, where no water-flush toilet fixtures are connected, shall be constructed with a septic tank and seepage system at least 1/2 the capacity specified for usual house sewerage systems.
('66 Code, § 57-13)