Septic tanks shall:

(1) Have at least two compartments with the first compartment liquid volume equal to one-half to two-thirds of the total liquid volume. This standard may be met by one tank with two compartments or by two single compartment tanks in series.

(2) Have the following minimum liquid volumes:

(a) For a single family residence use Table VII, Required Minimum Liquid Volumes of Septic Tanks:

(b) For OSS treating sewage from a residential source, other than one single-family residence, two hundred fifty gallons per bedroom with a minimum of one thousand gallons;

(c) For OSS treating sewage from a nonresidential source, three times the design flow.