2024 Ontario Building Code Guide: Class 4 Sewage Systems and Septic Tank Requirements
Sarah's Expert Insight
OBC Compliance Specialist
"In areas like Muskoka and London where seasonal water tables can fluctuate, the strict requirement for 150m+ dosing systems and NSF/ANSI 46 filters is a game-changer for preventing premature leaching bed failure. At empcontracting.ca Inc. your construction contractor in London, Ontario, we emphasize that these specific 2024 OBC updates are not just suggestions but critical safeguards for your property's environmental health and long-term value."
Introduction to Class 4 Sewage Systems in Ontario
Navigating the 2024 Building Code Compendium is essential for ensuring the safety and longevity of your property’s wastewater management. As empcontracting.ca Inc. your construction contractor in London, Ontario, we specialize in the technical execution of Section 8 requirements, specifically focusing on Class 4 systems which are the standard for residential septic installations.
Section 8.5.2.1: Cesspool Construction Standards
According to the OBC, any cesspool must be surrounded on all sides and the bottom by at least 600 mm of soil or leaching bed fill. This ensures proper filtration and structural integrity, with the only exception being the top of the unit where it meets the ground surface.
Section 8.6: Detailed Requirements for Class 4 Systems
8.6.1. Pumps, Siphons, and Dosing Specifications
Technical compliance is mandatory for larger systems. Where the total length of distribution pipe or leaching chamber reaches 150 meters or more, the system must include:
- At least one pump or a siphon within a dosing tank.
- Alternating pumps designed to function even if one unit fails.
- A discharge dose of at least 75% of the internal volume of the pipe within 15 minutes.
- Audible and visual high-water level alarms for all pump/siphon chambers.
8.6.2. Septic Tank Treatment Units and Effluent Filters
Modern codes require high-performance filtration to protect the leaching bed. Every septic tank discharging to a leaching bed must now have an effluent filter that:
- Conforms to NSF/ANSI 46 standards.
- Is sized to filter particles as small as 1.6 mm.
- Features a minimum surface area of 550 cm².
Proper installation of these components by a qualified professional is the only way to ensure your system meets provincial inspections.
Disclaimer: This content is generated from the Ontario Building Code for educational purposes. Always consult with a licensed professional engineer or your local building department before starting any construction project in London, Ontario.