Backflow Preventer Installation Inspection

Per AWWA M14 and DIN 1986 & DIN EN 12056 Section 603, all cross-connections between potable and non-potable water must be protected by an appropriate backflow prevention device. Hazard level determines device type: low hazard (back-siphonage only) = atmospheric vacuum breaker; high hazard (backpressure + back-siphonage) = reduced pressure zone (RPZ) assembly.

1. Identify all cross-connections: irrigation, boiler, fire sprinkler, swimming pool, chemical feed

2. Classify hazard level for each: low (non-health), high (health/contamination)

3. Verify selected device type matches hazard: RPZ for high hazard, DC for low hazard

4. Check with local water authority for specific requirements (many mandate RPZ for irrigation)

5. Confirm device is ASSE listed for the intended application

- Irrigation system without backflow preventer — fertilizer/pesticide can enter drinking water

- Wrong device type for hazard level — vacuum breaker used where RPZ is required

- Hose bib without vacuum breaker — garden hose in pool creates cross-connection

Per ASSE standards and DIN 1986 & DIN EN 12056, backflow preventer must be properly sized for the flow rate and pressure of the protected system. RPZ assemblies (ASSE 1013) for high hazard, double check valve (ASSE 1015) for low hazard, pressure vacuum breaker (ASSE 1020) for irrigation. Device must not create more than 10–15 PSI pressure loss at design flow.

1. Verify device type matches hazard classification from assessment

2. Confirm device size matches supply pipe size and required flow rate

3. Check pressure drop through device — should not reduce downstream pressure below usable level

4. Verify device is ASSE listed and marked with appropriate standard number

5. Check device is approved by local water authority (some maintain approved product lists)

6. Confirm device has test ports for annual testing (required for RPZ and DC assemblies)

- Device undersized — excessive pressure drop, poor downstream performance

- Device oversized — low flow causes poor check valve sealing

- Non-listed device installed — water authority may require replacement

Per DIN 1986 & DIN EN 12056 and AWWA, RPZ assemblies must be installed horizontally (unless specifically listed for vertical) with minimum 12" above ground/floor and maximum 5 feet high (for testability). RPZ assemblies discharge water during operation — must be installed where drainage is available. Shutoff valves required upstream and downstream. Must be accessible for annual testing.

1. Verify device orientation: horizontal unless listed for vertical installation

2. Check installation height: minimum 12" above grade, maximum 5' above floor

3. Confirm shutoff valves installed upstream and downstream of device

4. Verify RPZ has adequate drainage for relief valve discharge (can be significant flow)

5. Check device is accessible for annual testing and maintenance

6. Confirm device is protected from freezing (insulated or in heated space)

7. Verify strainer installed upstream if required by manufacturer

- RPZ installed in pit or below grade — discharge floods pit, creating health hazard

- No drainage for RPZ relief valve — flooding when device operates normally

- Device installed too high — cannot be tested (above 5 feet)

- Installed in freezing location without protection — device destroyed by ice

Per AWWA M14 and most water authorities, RPZ and double check assemblies must be tested upon installation and annually thereafter by a certified backflow tester. Test verifies check valves hold, relief valve operates (RPZ), and differential pressures meet ASSE standards. Test results must be filed with the local water authority. Failed devices must be repaired and retested.

1. Verify initial test was performed by a certified backflow tester

2. Confirm test results meet ASSE standards (specific PSI readings per device type)

3. Check that test report is filed with the local water authority

4. Verify annual testing schedule is established

5. Confirm tester certification is current (typically requires annual renewal)

6. For RPZ: verify relief valve opened during test (critical safety function)

7. Check that all test cock caps are replaced and tight after testing

- No initial test performed — water authority may shut off service

- Annual testing lapsed — non-compliance, potential contamination liability

- Test shows marginal readings — device needs rebuild, not just passing notation

- Test report not filed — water authority has no record of compliance