The Ontario Building Code | Connection of Overflows from Rainwater Tanks
7.4.2.2. Connection of Overflows from Rainwater Tanks
(1) Where an overflow from a rainwater tank is connected to a storm drainage system, it shall be connected by,
(a) an air break, or
(b) a backwater valve installed on the storm drainage pipebefore the connection to the storm building drain.
In Plain Language
Where a rainwater tank has an overflow, that overflow must be connected to the drainage system in specific approved ways, preventing overflow water from causing water damage or backing up into the tank improperly.
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.