House sewers shall not be less than 4 inches in diameter. The grade shall be at least 1/4 inch per foot for 4-inch sewers and shall not be less than 1/8 inch per foot for larger sizes. House sewers shall be laid with tight joints to a septic tank in a straight line and on a uniform grade except where accessible manholes or surface cleanouts are provided at changes of direction or grade. Pipe for the house sewers shall be of cast iron, with leaded or equal joints, to a point at least 15 feet beyond the foundation wall of any cellar or basement. Portions of house sewers within 74 feet of a well shall be of cast iron with leaded or equal joints, but no portion of the sewer, however constructed, shall be within 25 feet of a well. Greater separating distance may be required for wells with higher rates of pumpage than for residential use. No sewer shall be located within 25 feet of a cellar drain or ground or surface water drain unless the pipe is of cast iron with leaded or equal joints.
('66 Code, § 57-11)