OBC DIVISION B · PART 8 — SEWAGE SYSTEMSUpdated for the 2024 Ontario Building Code
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Section 8.8 — Class 5 Sewage Systems
Full text of Section 8.8 (Class 5 Sewage Systems) — Division B, Part 8 (Sewage Systems) of the 2024 Ontario Building Code, with every article reproduced below.
8.8.1.Application
8.8.1.1.Prohibited Installation permalink →
(1) Except as provided in Article 8.8.1.2., a Class 5 sewage system shall not be installed.
8.8.1.2.Acceptable Installation permalink →
(1) A Class 5 sewage system may be installed in the following circumstances:
(a) where the proposed use of the sewage system is for a temporary operation, excluding seasonal recreational use, not
exceeding 12 months in duration,
(b) to remedy an unsafe sewage system where the remediation of the unsafe condition by the installation of a Class 4
sewage system is impracticable,
(c) to upgrade a sewage system serving an existing building, where upgrading through the use of a Class 4 sewage
system is not possible due to lot size, site slope or clearance limitations, or
(d) as an interim measure for a lot or parcel of land until municipal sewers are available, provided that the municipality
undertakes to ensure the continued operation of an approved hauled sewage system until the municipal sewers are
available.
(2) Where a Class 5 sewage system is installed, a written agreement for the disposal of sanitary sewage from the sewage
system shall be entered into with a hauled sewage system operator.
8.8.2.General Requirements
8.8.2.1.Construction Requirements permalink →
(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.
(2) The device required in Sentence (1) shall be designed to provide suitable advance warning to the building occupants
considering
(a) the total daily design sanitary sewage flow,
(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 tank is located in an area subject to flooding,
and
(c) terminates at least 3.5 m away from any air inlet, window, or door.
(4) A vent from a holding tank may connect into the venting system of the building served by the holding tank provided
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.
8.8.2.2.Sizing of Holding Tanks permalink →
(1) All holding tanks used in residential dwellings shall have a minimum 7 day holding capacity based on the total daily
design sanitary sewage flow.
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Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.