Annual Backflow Prevention Valve Testing and Maintenance in Richmond Hill

• Definition: A cross-connection refers to any connection between a drinking water system and a potential source of pollution or contamination.
• Purpose: Identifying and controlling cross-connections is essential to prevent the backflow of contaminated water into the clean water supply.

• Definition: Backflow is the reversal of the normal water flow direction in a plumbing system.
• Causes: Backflow results from two main factors, back siphonage, and back pressure.
  • Back Siphonage: Caused by negative pressure in a public water system, similar to drinking through a straw, it can occur during water supply stoppages, firefighting, water main breaks, or high water withdrawal rates.
  • Back Pressure: Occurs when a non-potable water system’s pressure exceeds the municipal water system’s supply pressure, caused by booster pumps, elevated piping, interconnections, or temperature increases.

• Definition: A backflow preventer is a device designed to prevent backflow.
• Types: Various types are available, selected based on the application and required protection level.
• Testing Requirements: Some types require periodic testing by trained professionals to ensure proper functioning.

• Periodic testing is necessary for several reasons:

  • Functioning Verification: Mechanical backflow preventers may develop fouling, wear, or fatigue over time. Testing ensures they work as intended.
  • Bypass Prevention: Backflow preventers can be bypassed or tampered with, compromising their effectiveness. Regular testing identifies issues or unauthorized modifications.
  • Qualified Testing: Testing should be conducted by certified individuals for accurate and reliable results.

Controlling cross-connections is vital to prevent water contamination, categorizing backflow hazards based on potential impact, and ensuring water suppliers prioritize public water system safety and integrity.

1. Double Check Valve Assembly (DCVA): Suitable for “moderate hazard” facilities, providing protection against low to moderate risk of backflow incidents.

2. Reduced Pressure Principle Assembly (RP): Required for “severe hazard” facilities, offering comprehensive protection against high-risk backflow incidents.

• Back Pressure: Occurs when private system pressure exceeds the city’s due to factors like pumps or temperature changes.
• Back Siphonage: Happens when city pressure drops below private systems, often during firefighting or water main breaks.