OBC DIVISION B · PART 8 — SEWAGE SYSTEMSUpdated for the 2024 Ontario Building Code

Section 8.1 — General

Full text of Section 8.1 (General) — Division B, Part 8 (Sewage Systems) of the 2024 Ontario Building Code, with every article reproduced below.

8.1.1.Scope

8.1.1.1.Scope permalink →

(1) The scope of this Part shall be as described in Subsection 1.3.3. of Division A.

8.1.1.2.Definitions permalink →

(1) Except as provided in Sentence (2), words that appear in italics are defined in Article 1.4.1.2. of Division A and in the Building Code Act, 1992. (2) In this Part, Soil means in-situ, naturally occurring, unconsolidated mineral or organic material, at the earth's surface that is at least 100 mm thick and capable of supporting plant growth, and includes material compacted or cemented by soil forming processes, but does not include displaced materials such as gravel dumps, mine spoils, or like deposits.

8.1.2.Application

8.1.2.1.Classification of Systems permalink →

(1) All sewage systems shall be classed as one of the following: (a) Class 1 — a chemical toilet, an incinerating toilet, a recirculating toilet, a self-contained portable toilet and all forms of privy including a portable privy, an earth pit privy, a pail privy, a privy vault and a composting toilet system, (b) Class 2 — a greywater system, (c) Class 3 — a cesspool, (d) Class 4 — a leaching bed system, or (e) Class 5 — a system that requires or uses a holding tank for the retention of hauled sewage at the site where it is produced prior to its collection by a hauled sewage system.

8.1.2.2.Operation and Maintenance permalink →

(1) Operation and maintenance of sewage systems shall comply with Section 8.9.

8.1.3.Limitations

8.1.3.1.Discharge permalink →

(1) Except as provided in Sentences (2) to (6), the sewage system shall be designed and constructed to receive only sanitary sewage of domestic origin. (See Note A-8.1.3.1.(1)) (2) Where laundry waste is not more than 20% of the total daily design sanitary sewage flow, it may discharge to a sewage system. (3) Where industrial process waste water is treated to the contaminant levels found in domestic sanitary sewage, it may discharge to a leaching bed provided the treatment unit and sewage system are designed in accordance with good engineering practice. (See Note A-8.1.3.1.(3)) (4) Where kitchen waste water from a restaurant has passed through an operating grease interceptor, it may discharge to a leaching bed provided the sewage system has been designed in accordance with good engineering practice. (5) Waste water from a kitchen equipped with a garbage grinder may be directed to the sewage system provided the system has been designed to accept such waste water. (6) Water softener and iron filter discharge may be directed to the sewage system provided the system has been designed to accept such discharges. (7) Storm sewage shall not be discharged into a sewage system. (8) The interceptor required in Sentence (4) shall (a) have a minimum flow rate as required by Sentence 7.4.4.3.(8) using a 60 second drain down time, and (b) conform to, (i) CSA B481.1, “Testing and rating of grease interceptors using lard,” or (ii) CSA B481.2, “Testing and rating of grease interceptors using oil.”

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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.