2024 Ontario Building Code Septic Tank Standards | empcontracting.ca Inc. Guide
Sarah's Expert Insight
OBC Compliance Specialist
"At empcontracting.ca Inc. your construction contractor in London, Ontario, we find that the 300 mm access depth rule is the most commonly overlooked requirement in rural Muskoka and London developments. Properly anchoring tanks against hydrostatic pressure is non-negotiable in high-water table areas to prevent catastrophic tank displacement and ensure long-term system performance."
Understanding the 2024 Building Code Compendium Section 8.2.2.3 is critical for ensuring environmental safety and legal compliance for any property requiring on-site sewage systems. As empcontracting.ca Inc. your construction contractor in London, Ontario, we ensure every installation meets these rigorous engineering standards.
Septic Tank Capacity and Occupancy Requirements
The OBC dictates strict minimums for tank capacity to prevent system failure. The minimum working capacity must be at least 3,600 L. For residential projects, the capacity must be twice the daily design flow, whereas non-residential projects require three times the daily flow.
Compartment Design and Sewage Flow
To ensure proper treatment, every tank must have at least two compartments. The first compartment must be the largest, holding at least 1.3 times the daily design flow (minimum 2,400 L), with subsequent compartments sized at 50% of the first. This multi-stage process is vital for the separation of solids and liquids.
Installation, Burial Depth, and Anchoring
Structural integrity is a primary focus of Section 8.2.2.3. Tanks cannot be buried deeper than their design rating. Furthermore, in regions with high water tables, tanks must be securely anchored to counteract hydrostatic pressures that could otherwise cause the tank to shift or float.
Connecting Multiple Tank Systems
When multiple tanks are used in a series, empcontracting.ca Inc. your construction contractor in London, Ontario, follows strict OBC piping protocols:
- A minimum pipe slope of 2 percent between tanks.
- The use of flexible, watertight seals to allow for differential movement.
- Ensuring all tanks in the series meet the minimum 3,600 L capacity threshold.
Maintenance Access and Depth Standards
For long-term viability, access openings must be positioned to allow for easy pumping and servicing. Under the 2024 code, access openings must not be located more than 300 mm below the ground surface unless specific exceptions apply. Liquid depth must generally be maintained at a minimum of 1,000 mm to ensure effective settling.
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.