New Backflow Preventer Dripping: Debris on Check Valve Seat

Newly installed irrigation system. Backflow preventer drips from the relief port (air vent). ¼ gallon overnight. Is this normal? Will it affect the water bill?

Not Normal—Debris on Seat

Backflow preventers should not drip. A tiny contaminant (solder flux, pipe shavings, Teflon tape) on a check valve seat prevents full closure.

Fix Attempts

1. Flush via test ports: Open the ¼" test cocks briefly to blow debris out.
2. If persistent: Disassemble and clean the check valves. Caution: Internal springs can eject parts dangerously. Consider a pro if unfamiliar.

Water Bill Impact

Negligible. Most meters don't register flows this low.

Provide backflow model/manufacturer for specific disassembly guidance.