(a) Sanitary sewers shall be designed to flow half full. The quantity of sewage shall be determined by use of 100 gallon per day per capita for the entire service or drainage area which may drain through the area being developed, plus wastewater flow from industrial plants and major institutional and commercial facilities. Water use data, or other justification upon which a better flow estimate is based, may be submitted for consideration. In addition, a peaking factor shall be applied which can be calculated using the ratio of peak hourly flow to design average flow chart provided in the Recommended Standards For Wastewater Facilities, latest edition. All sanitary sewers shall be designed to have a minimum velocity of two feet per second.
(b) The minimum size of a main sewer shall be eight inches in diameter and shall be constructed in accordance with the specifications for installation of sanitary and storm sewers on file in the Service Department. The minimum size house connection shall be four inch.
(c) Sanitary sewers shall be constructed at a depth sufficient to serve all the tributary area which may drain through the area being developed. The sanitary sewer mains shall be constructed not less than five feet deep and shall be deep enough to provide clearance for storm sewers and water mains and to provide not less than three feet of fall between the hydraulic gradient of the sewer and the basement, but in no case shall the top of the main sewer be less than five feet below the finished street grade.
(d) House connections shall be connected to the main sewer by use of four inch by eight inch, or four inch by twelve inch "Y" branches on eight-inch and twelve-inch sewers and by four inch stubs on sewers larger than twelve inches.
(e) House connections shall be laid on a minimum slope of two percent.
(f) Where a pipe enters a manhole two feet or more above the manhole invert, a drop manhole is necessary. The drop manhole shall have an outside drop connection as shown in the City's standard drawings. Where the difference in elevation between the incoming sewer and manhole invert is less than two feet, the invert shall be filleted to prevent solids deposition.
(g) Standard manholes shall be constructed at all junctions of two or more sewers, at all changes in size of pipe, at all changes in grade, at all changes in alignment, at the ends of all main sewers, and at intervals not to exceed 400 feet.
(h) Manholes, sewers, and appurtenances shall be constructed in accordance with the standard drawings and specifications on file in the Service Department.
(i) All sanitary sewer plans shall be submitted to the Environmental Protection Agency (EPA) for approval. The developer shall prepare all forms and pay all fees necessary for submission of the plans to the EPA. All sanitary sewer plans shall be prepared in accordance with the Recommended Standards For Wastewater Facilities, latest edition.
(Ord. 95-387. Passed 12-5-95; Ord. 19-289. Passed 12-10-19.)