OBC Plumbing Standards: Backflow Prevention and Water System Safety in Ontario
Sarah's Expert Insight
OBC Compliance Specialist
"As a senior consultant at empcontracting.ca Inc., your construction contractor in London, Ontario, I cannot overstate the importance of integrating proper thermal expansion and backflow protection in modern builds. In areas like London and Oakville, adhering to these specific CSA standards during the rough-in phase is the only way to prevent catastrophic pressure failures and ensure the long-term safety of the municipal potable water supply."
At empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize compliance with the 2024 Ontario Building Code (OBC) to ensure the safety and longevity of your plumbing infrastructure. This guide breaks down essential requirements for temperature relief, backflow prevention, and thermal expansion.
7.6.2.1. Temperature-Relief and Backflow Prevention
Safety Valve Requirements
Per OBC 7.6.2.1.(6), temperature-relief valves must have a sensing element located within the top 150 mm of the tank. They must be designed to discharge enough water to ensure the tank temperature never exceeds 99°C. Furthermore, no shut-off valves are permitted between the tank and the relief valves or on the discharge lines.
Potable Water Protection
Protection from contamination is paramount. Connections to potable water systems must be designed to prevent non-potable substances from entering the supply. Backflow preventers must be selected and installed according to the CSA B64.10 standard, and connections between different potable systems require the consent of the water purveyor.
7.6.1.8. Specialized Water Systems
Solar Domestic Hot Water
Solar heating systems for potable water must be installed in strict conformance with CAN/CSA-F383. This ensures that packaged solar domestic hot water systems meet provincial efficiency and safety benchmarks.
Mobile Home Water Services
A water service pipe for a mobile home must be at least NPS ¾ and terminate above ground. It requires a tamperproof connection, a protective concrete pad, frost heave protection, and a curb stop with drainage capabilities for portions above the frost line.
7.6.1.9 - 7.6.1.11. System Protection Measures
Water Hammer and Thermal Expansion
Provision must be made to protect the distribution system from the damaging effects of water hammer. Additionally, where thermal expansion occurs, protection must be provided for check valves, backflow preventers, and pressure-reducing valves to maintain system integrity.
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.