5 Steps to Fix a Pool Pump That Keeps Losing Prime

Check the pump lid O-ring Take it off, clean it, lubricate it with silicone pool lube, and reseat it. Tighten the lid evenly — don’t overtighten. Replace the O-ring if it’s cracked or flattened.

Inspect the drain plugs and threaded fittings Drain plugs on the pump housing can vibrate loose, and their O-rings can fail. Also check the pump inlet, check valve, and any valves for hairline cracks or loose unions.

Run a garden hose test if the pump is below water level With the pump running, spray water over each suction-side fitting. If the pump primes and holds, you found the leak.

Rule out simple issues first Low water level, a stuck weir door, or a clogged skimmer basket can cause air suction. If the water level is fine and the basket is clean, move on to the leak.

Start with the O-ring — it’s the most common cause Nine times out of ten, a bad or poorly seated O-ring is the culprit. Fix that before chasing more complex leaks.