DRAINAGE PIPING INSTALLATION
Philadelphia Code Subcode P, § 704
in effectSECTION 704 DRAINAGE PIPING INSTALLATION
P-704.1 Slope of horizontal drainage piping. Horizontal drainage piping shall be installed in uniform alignment at uniform slopes. The slope of a horizontal drainage pipe shall be not less than that indicated in Table P-704.1 except that where the drainage piping is upstream of a grease interceptor, the slope of the piping shall be not less than 1/4 inch per foot (2-percent slope). Building sewer force mains are not permitted.
TABLE P-704.1
SLOPE OF HORIZONTAL DRAINAGE PIPE
SIZE (inches) | MINIMUM SLOPE (inch per foot)
2-1/2 3 or less | 1/4 a
3 4 to 6 | 1/8 a
8 or larger | 1/16 a
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P-704.5 Dead ends. In the installation or removal of any part of a drainage system, dead ends shall be prohibited. Cleanout extensions and approved future fixture drainage piping shall not be considered as dead ends.
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Source: City of Philadelphia, The Philadelphia Code and Home Rule Charter (American Legal Publishing, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/philadelphia/latest/philadelphia_pa/0-0-0-312315Fetched: 10/27/2026