Open pool pump strainer pot with replacement o-ring and basket on a daylight equipment pad

How To Prime a Pool Pump

If your pool pump is running but no water is moving, you have an air-locked pump that needs to be primed. This is one of the most common pool problems homeowners hit, especially right after opening for the season or after running a pump dry by accident. The good news: priming a pool pump is a 5-minute job, no special tools required, and once you understand the cause, you can usually keep it from happening again.

This tutorial walks through priming a standard residential pool pump from start to finish. The steps are the same whether you run a single-speed, two-speed, or variable-speed pump — the only thing that changes is how you start and stop the motor.

What you’ll need

  • A garden hose with a working spray nozzle
  • A bucket or pitcher of water (a backup if your hose is far from the pad)
  • A clean pump lid o-ring (replace if cracked or flattened — this is the #1 cause of repeat priming problems)
  • A spare strainer basket if yours is broken or warped
  • Silicone-based pool lubricant for the lid o-ring (never petroleum jelly — it swells the rubber)

Before you start: turn power off

Safety first: always switch the pump off at the breaker before opening the strainer pot. A pump that powers on with the lid off will throw water and parts across the equipment pad and can pull a hand or rag into the impeller.

Step-by-step: priming your pool pump

1Turn the pump off and rotate the multiport valve to “Filter.”

If you have a sand or DE filter with a multiport valve, set it to Filter. If you have a push-pull (slide) valve, push it down to the filter position. This gives the pump a clear, low-resistance path to push water once it primes.

2Close all skimmer and main drain valves except one skimmer.

You want the pump pulling from one source while it primes. Once it’s running steady, you can reopen the others. If your system has just one suction line, skip this step.

3Open the pump lid and inspect the strainer basket.

Unscrew the clear lid on top of the pump (most twist counter-clockwise). Pull out the strainer basket and check for cracks, broken tabs, or leaves jammed in the slots. A cracked basket lets debris through to your impeller and can also let air leak in. Empty it, rinse it, and put it back.

4Check the lid o-ring.

Remove the o-ring from inside the lid and look for cracks, flat spots, or stretched sections. If it doesn’t snap back to a round shape, replace it. A bad lid o-ring will keep sucking air no matter how many times you prime — this is the single most common reason pumps lose prime over and over.

If the o-ring looks good, wipe it clean and apply a thin film of silicone-based pool lubricant before setting it back in place.

5Fill the strainer pot with water.

Stick your garden hose into the open pump and fill the basket housing until water is right at the top — spilling over slightly is fine. You’re trying to physically replace the air inside the pump with water so the impeller has something to grab onto.

6Reinstall the lid and hand-tighten only.

Drop the lid back on, line up any locking tabs, and hand-tighten. Do not use a wrench or strap wrench — the lid is designed to seal with the o-ring alone, and overtightening damages the threads and the o-ring.

7Turn the breaker back on and start the pump.

The pump will run loud and rough for the first 30 to 90 seconds while it purges air through the system. You should see bubbles and frothy water inside the strainer pot, then a steady stream of clear water. Once the water is clear and the pot is full, the pump is primed.

8Open the rest of your suction valves.

Slowly reopen your other skimmer and main drain valves one at a time. Watch the pressure gauge: it should stay steady or rise slightly. If pressure drops or you hear gurgling, close that valve and check it for an air leak.

Replacement parts you may need

If your pump keeps losing prime, the fix is almost always one of these three parts. They’re inexpensive and ten minutes to install:

Pool pump strainer top lid gasket o-ring replacement

Pump Strainer Top Lid Gasket

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Hayward SPX1680GA PowerFlo LX pump strainer basket replacement

Hayward PowerFlo LX Strainer Basket (SPX1680GA)

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Hayward VL series strainer lid and basket replacement kit

Hayward VL Series Strainer Lid + Basket Kit

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Troubleshooting: pump won’t hold prime

If your pump primes but loses suction within a few minutes, you almost certainly have an air leak somewhere on the suction side. The pump is pulling air in along with water, and once that air bubble reaches the impeller, the prime breaks. Check these in order:

  • Pump lid o-ring — the most common culprit. Replace if there’s any doubt.
  • Skimmer suction-side plumbing — look for visible cracks, especially at PVC unions and elbows.
  • Drain plugs on the pump body — if they’ve been opened for winterizing, they’re a common loose-fit leak point.
  • Water level — if your pool is below the middle of the skimmer mouth, you’re sucking air through the skimmer. Top the pool off and try again.

How long should a pump take to prime?

A properly primed pump should be moving clear water within 30 to 90 seconds. If you’re past two minutes and still seeing air, shut it off — running a pump dry burns out the shaft seal in as little as five minutes, and that’s a far more expensive repair. Recheck your suction lines, refill the strainer pot, and try once more.

If your pump still won’t prime after a careful second attempt, you most likely have a suction-side leak that needs to be tracked down. The team at PST Pool Supplies can help you diagnose it — reach out and we’ll walk through the symptoms with you.

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