The Ontario Building Code | Backfill of Pipe Trench
7.3.5.1. Backfill of pipe Trench
(1) Where piping is installed underground, the backfill shall be carefully placed and tamped to a height of 300 mm over the top of the pipe and shall be free of stones, boulders, cinders and frozen earth.
In Plain Language
Backfill placed over buried piping must be carefully placed and tamped to a specified height above the pipe before heavier fill goes on top, protecting the pipe from being crushed or displaced.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.