(a) Refer to the State of Michigan Plumbing Code, Chapter 4, Table P-404.0 and P-405.0. Material for sanitary sewers shall comply to the State of Michigan Plumbing Code, Table P-403.3. The size of the sanitary sewer shall be sized in accordance with the number of fixtures it serves but shall not be less than four inches in diameter. All commercial sanitary sewers shall be at least six inches in diameter from the City’s main sewer to five feet outside of the building.
(b) (1) Building storm sewers, roof conductors, parking lots or other site developments shall be sized to Table P-803.0 of the BOCA National Plumbing Code commentary or shall be of a calculation using the rational method. The Manning Formula shall be used to select the appropriate pipe size. On-site retention/detention will be required if the storm drainage outlet is incapable of handling the developed runoff. The size of the storm sewer service lead shall be a minimum of six inches. All parking lots shall have catch basins installed and the number of catch basins shall be based on the area to be drained. Exception:
a. Parking lots which back up to an open drainage area;
b. A storm sewer is not available; and/or
c. The cost for installing a new storm sewer to the area is cost-prohibitive for the City.
(2) Tapping the main storm sewer or catch basin requires installation and inspection pursuant to the rules of the Department of Public Works and Utilities.
(Ord. 3268, passed 1-24-1994; Ord. 3630, passed 12-13-2004)