Pool Pump Not Priming? 8 Things to Check

Your pool pump is running, but the basket stays half empty, the water barely moves or air bubbles spit out of the returns. In almost every case the pump is sucking air instead of water. Work through these checks in order. Most take five minutes and cost nothing.

Tip: if the pump hasn’t primed within a few minutes, switch it off. Running dry overheats the pump and damages the shaft seal.

1. The pool water level is too low

If the water drops below the skimmer opening, the pump gulps air. Keep the level about halfway up the skimmer mouth, and top up after backwashing and in hot, windy weather.

2. The pump basket was empty when you started it

After cleaning the basket or a long stop, the pump needs water to get going. Fill the basket with a hose or bucket, close the lid firmly and start the pump.

3. The lid isn’t sealing

A dry, cracked or dirty lid O-ring lets air in. Clean it, check it for cracks and wipe it with a silicone lubricant, not petroleum jelly, which damages rubber. Make sure the lid is closed evenly and tight.

4. Something is blocking the suction

Check the skimmer basket, the pump basket and the skimmer’s weir flap. Leaves in the suction pipe or a jammed impeller also starve the pump. With the power off, look into the pump for debris around the impeller.

5. An air leak on the suction side

Bubbles coming out of the returns are the classic sign. Check the unions and fittings between the pool and the pump for cracks or loose joints, and listen for hissing while the pump runs. A small amount of shaving foam on a joint gets sucked in if it leaks.

6. The pool cleaner hose is leaking

A suction pool cleaner with a split hose section or a loose connection lets air straight into the system. Remove the cleaner and see if the pump primes without it.

7. A valve is closed or the pump sits too high

Make sure every valve on the suction side is open. Self-priming pumps can only lift water so far: a Speck BADU Porpoise, for example, can sit up to 3 m above or below the water level. A pump mounted higher, or with a very long suction pipe, struggles to prime.

8. The pump itself is worn

If the motor hums but won’t turn, the capacitor may have failed. A screeching or grinding noise points to worn bearings. A leak under the pump usually means a worn shaft seal. These are all repairable with parts from our pool components and spares, but if the pump is old and tired, a new one is often the better buy.

Frequently asked questions

How long should a pool pump take to prime?

Usually a minute or two with a full basket. If it hasn’t primed after a few minutes, stop it and look for an air leak or low water level.

Why are there air bubbles in my pool returns?

Air is getting in on the suction side: a low water level, a leaking lid O-ring, a loose union or a split pool cleaner hose.

Can a pool pump run without water?

Not for long. Running dry overheats the pump and destroys the shaft seal within minutes.

What size pool pump do I need?

It depends on your pool’s volume. Our pool pump size guide shows you how to work it out.

Time for a new pump?

We stock Speck and Quality pool pumps with delivery anywhere in South Africa. Tell us your pool size and your current pump on WhatsApp 012 881 1962 and we’ll match a replacement, free. Or browse all swimming pool pumps.