Sewage collection systems, when installed in subdivisions, shall be in accordance with the following standards and provisions and pursuant to title 8 of this code:
A. Materials Of Construction: Metallic and nonmetallic materials may be used separately and in combination to construct the component parts of a sewer collection system, provided:
1. The material shall be either a plastic PVC, SDR-35; ductile iron class 51, or other materials approved by the city engineer.
2. The material shall be capable of withstanding, with ample safety factors, the internal and external forces with which it may be subjected in service.
3. Material and equipment shall be so selected as to mitigate corrosion, electrolysis and deterioration.
4. Orangeburg or other fiber pipe shall not be used for sewer main or laterals.
B. Sewer Mains And Laterals:
1. Gravity Sewer Mains: Sewage shall be collected in a network of sewer mains laid within the rights of way of public streets leading to the sewage disposal system. All sewer mains shall not be less than eight inches (8") in diameter and of sufficient size to carry all sewage which can reasonably be anticipated from the full expected use of all lots and areas served by the mains. All sewers shall be designed and constructed to give mean velocities, when flowing full, of not less than two feet (2') per second, based on the "n" value of 0.013. The basic slope requirements and design shall comply with standard specifications for public works construction.
Slopes less than those required for the two feet (2') per second velocity, when flowing full, may be permitted with written approval from the city engineer. Whenever decreased slopes are selected, the design engineer shall submit calculations supporting this criteria to the city engineer.
2. Service Connection Laterals: A service connection lateral of not less than four inch (4") nominal size shall be placed to each lot from the lot line to the sewer main with a two percent (2%) minimum slope.
3. Trenching: All sewer mains and laterals shall be placed and the back fill compacted prior to the surfacing of the streets affected. City street excavation permits shall not be required for trenching required to place water and sewer systems in subdivision streets prior to street surfacing when the construction of such systems is secured by a subdivision bond or deposit. No water or sewer mains or laterals shall be covered until forty eight (48) hours after written notice of such placement and request for inspection has been delivered to the city and the system has passed the hydrostatic and other tests required by the city.
C. Manholes: Standard manholes shall be installed at the end of each line, with a continuous stub out, at all intersections of other sewer lines, at all changes in grade and changes in line size or adjustment. Maximum spacing for manholes shall be three hundred (300) linear feet maximum, unless approved by the city engineer, for all lines smaller than twenty four inches (24") in diameter and three hundred feet (300') for lines twenty four inches (24") and larger. Manholes shall be constructed such that the energy gradient through the manholes is maintained.
D. Storm Water Drains: No storm water drains shall be connected to any sewer main or lateral. (1973 Code § 16.24.100)