The Ontario Building Code | Prevention of Accumulation and Ingress
5.7.1.1. Prevention of Accumulation and Ingress
(1) Except as provided in Sentence (3), the building shall be located, the building site shall be graded or catch basins shall be installed so that surface waterwill not accumulate against the building.
(2) Except as provided in Sentence (3), the foundation walls shall be constructed so that surface water will not,
(a) enter the building, or
(b) damage moisture susceptible materials.
(3) Buildings specifically designed to accommodate accumulation of water at the building or the ingress of water need not comply with Sentence (1) or Clause (2)(a).
Section 5.8. Moisture in the Ground
5.8.1. Foundation and Floor Drainage
In Plain Language
Except in a specific permitted case, the building must be located, and the building site graded, to prevent the accumulation of water against the building and to prevent water ingress into the structure.
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.