The Ontario Building Code | Construction Requirements
220.127.116.11. Construction Requirements
(1) All Class 5 sewage systems shall be equipped with a device that shall produce an audible and visual warning alarm so located to warn that the sewage system is nearing capacity.
(b) the location of the Class 5 sewage system, and
(c) the response time of the hauled sewage system contractor.
(3) Except as provided in Sentence (4), all holding tanks shall be provided with a vent that,
(a) is not less than 3 in. trade size,
(b) terminates at least,
(i) 300 mm above finished grade with a vent cap, or
(ii) 600 mm above finished grade with a vent cap when the holding tankis located in an area subject to flooding, and
(4) A vent from a holding tank may connect into the venting ="http://thehandyforce.com/interior/bathroom-renovations/" title ="Toronto Bathroom renovation inspiration">venting system of the building served by the holding tankprovided that,
(a) the vent is not less than 3 in. trade size, and
(b) the installation of the vent shall conform to the requirements in Part 7.