How to prime a pool pump

What "losing prime" actually means

A pool pump can only move water, not air. Priming means filling the pump housing with water so the impeller can create suction and pull water through the plumbing. When air gets in — from a low water level, a clogged basket, or a bad seal — the impeller spins against nothing, water stops circulating, and the motor starts overheating.

Don't let it run dry. A pump without water can destroy its shaft seal in minutes and melt the housing. If it isn't pulling water after two minutes, shut it off.

Step-by-step: priming your pool pump

1. 1

   Turn the pump off at the breaker

   Shut the pump off at the timer and the breaker. Never open a pump lid or filter while the system is running or pressurized.

2. 2

   Release pressure from the filter

   Open the air relief valve on top of the filter and let all pressure escape until the gauge reads zero.

3. 3

   Set the valves to draw from the main drain

   Open the main drain valve fully and close the skimmer lines. The main drain sits below water level, so gravity helps push water toward the pump.

4. 4

   Open and clean the pump basket

   Unscrew the pump lid, lift out the strainer basket, and remove leaves and debris. Inspect the lid O-ring for cracks or dryness and lubricate it with silicone-based pool lube — a dry or damaged O-ring is the number one cause of a pump that won't hold prime.

5. 5

   Fill the pump housing with water

   Use a garden hose or a bucket to fill the pump basket housing to the top with water. This gives the impeller something to grab so it can pull the rest of the water through.

6. 6

   Reseal the lid hand tight

   Put the basket back, seat the O-ring, and tighten the lid by hand only. Tools can crack the housing and create the air leak you're trying to fix.

7. 7

   Turn the pump back on

   Switch the breaker on and start the pump. Keep the filter's air relief valve open so trapped air can escape, then close it once a steady stream of water comes out.

8. 8

   Watch for full flow, then reopen the skimmers

   Within 30–60 seconds you should see water swirling in the pump basket with no large air pockets. Once flow is steady, slowly reopen the skimmer valves and confirm the filter pressure returns to normal.

Common reasons a pump won't hold prime

• Water level too low. The water should sit at least halfway up the skimmer opening. In a Katy summer, evaporation alone can drop it enough to suck air.
• Dry or cracked pump lid O-ring. Clean it, lube it with silicone (never petroleum jelly), and replace it if it's flattened.
• Clogged skimmer or pump basket. Debris restricts suction long before it blocks it completely.
• Dirty filter. High filter pressure fights the pump. If the gauge reads 8–10 PSI above clean, clean the filter.
• Suction-side leak. A loose union, a bad valve stem, or a cracked pipe before the pump lets air in continuously.

Frequently asked questions

How long should it take a pool pump to prime?

A healthy pump should pull prime in about 30 to 60 seconds. If it runs longer than two minutes without water flow, shut it off — running dry burns up the shaft seal and can crack the housing.

Why does my pool pump keep losing prime?

Almost always an air leak on the suction side: a dry or cracked pump lid O-ring, a loose lid, a low water level below the skimmer mouth, a clogged skimmer or pump basket, or a leaking valve or union fitting before the pump.

Can I prime a pool pump without a hose?

Yes. Fill the pump housing with buckets of pool water instead. The goal is simply to get the housing full before you start the motor.

What if the pump still won't prime?

Check the water level, clean both baskets again, and look for bubbles in the pump lid while it runs. Persistent air usually means a suction-side leak or a worn impeller — that's the point to call a pool technician.

Filter clogged too? We offer pool filter cleaning service