Connected manholes shall not be separated by more than 500'. In addition, a manhole shall be placed at every location where changes in pipe size, pipe type, pipe direction, or intersection of other connecting pipes (other than single service laterals) occurs. A terminal manhole at the far upstream end of a line can be replaced by a cleanout if the cleanout is within 250' of the downstream manhole. The following chart shall determine manhole inside diameter.
Maximum Pipe Size Connected to Manhole (inch OD) | Inside Minimum Diameter of Manhole (feet) |
18" and less | 4.0 |
21" - 27" | 5.0 |
30" - 36" | 6.0 |
39" and greater | As Directed by City Engineer |
Manholes in the floodplain, or in areas normally subject to runoff water flows, shall have a waterproof seal in the top. Areas subject to known vandalism shall have bolt-down lids.