Facility Domestic Water Backflow Preventer Annual Testing Prep
This procedure outlines the critical pre-test preparation steps for facility domestic water backflow preventers ahead of their annual certified testing. Proper prep ensures accurate differential pressure readings, prevents equipment damage, and satisfies CSA B64 / local health authority requirements.
To standardize the preparatory actions required before conducting an annual backflow preventer test on a facility’s domestic water system. This SOP ensures all test cocks are accessible, the device is correctly isolated and pressurized, and all safety & documentation protocols are in place. Proper prep reduces risk of inaccurate test results, water hammer damage, and regulatory non‑compliance.
This procedure applies to all facility domestic water backflow preventers (reduced pressure zone [RPZ], double check valve [DCVA], or pressure vacuum breakers [PVB]) that require annual testing per local health authority or insurance requirements. It covers the pre‑test inspection, isolation, pressure equalization, and tool preparation. The actual certified test procedure (differential pressure drop measurement) is not included; that step must be performed by a certified backflow tester using a calibrated test kit and documented on the official test report.
- Lockout/tagout the building’s main water supply to the backflow preventer. Confirm zero flow through the device before opening any test cocks.
- Wear safety glasses, nitrile or leather gloves, and steel-toed boots. Use a bucket/drain hose to capture any water released during port bleeding.
- Never exceed the rated working pressure of the backflow preventer (typically 150 psi). Slowly open isolation valves to avoid water hammer. Depressurize before loosening any fittings.
- Assume potable water lines may contain bacteria (Legionella). Avoid aerosolizing water; drain into sanitary sewer. Wash hands after handling fittings.
- If the backflow preventer is installed in a pit or confined space, test atmosphere for oxygen deficiency and toxic gases before entry. Use a retrieval harness if required.
- Calibrated backflow test kit (e.g., Watts TK‑99, Ames 3000BT or equivalent), current calibration certificate within 12 months
- Adjustable wrenches (2×) and channel‑lock pliers
- Pressure gauge rated to 200 psi with ¼" NPT connection
- Bucket or drain hose (for capturing water from test cocks)
- Teflon tape / thread sealant (for sealing test kit connections)
- Flashlight and inspection mirror
- Lockout / tagout kit
- PPE: safety glasses, nitrile or leather gloves
- Pre‑test data sheet / checklist for recording static pressures and device details