Inflows of surface and excessive infiltration are prohibited. Such prohibited sources of inflow shall include, but not be limited to, the following: heating or cooling system discharges in excess of two thousand (2,000) gallons per day, stormwater connections, subwater drains, foundation drains, roof drains, street drains. Infiltration greater than two hundred (200) gallons per day per inch diameter per mile of pipe shall be prohibited. Variances may be granted as determined by the Public Works Department. (1952 Code § 8-11-10.07)