The Ontario Building Code | Class 4 Sewage Systems
8.9.3.4. Class 4 Sewage Systems
(1) Septic tanks and other treatment units shall be cleaned whenever sludge and scum occupy one-third of the working capacity of the tank.
In Plain Language
This article addresses maintenance requirements specific to Class 4 sewage systems in this part of the Subsection, building on the general Class 4 maintenance requirements set out earlier.
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.