The Ontario Building Code | Sewage Systems
11.4.3.6. Sewage Systems
(1) Where the performance level of an existing buildingis reduced under Article 11.4.2.5., upgrading of a sewage system which is adversely affected by the construction, increase in occupant load, increase in the total daily design sanitary sewage flow or change in amount or type of sanitary sewage shall be required in conformance with Part 8.