What is pool pump surge and how do you fix it?

Pool pump surge or pulsing is easy to identify just by listening to it. People can immediately tell that something isn’t right the first time around. The sound coming from your pool pump should be a constant hum (or roar, depending on your pool pump) and any change in noise level can make even novice pool owners take pause and look at their pool pump.

The reason for is intermittent flow of water into the pump (or the introduction of air) making the pump lose prime, reprimes itself, and then the cycle repeats itself.

Problems caused by pool pump surge or pulsing

A pool pump that surges or pulses can cause a lot of problems, the pulsing noise being the least of them. Here are the problems that may arise when your pump is pulsing and it isn’t dealt with immediately.

  • Pump burning out – One of the things that can happen is your pump’s motor can burn out due to the constant changing of impeller speed. Pool pumps weren’t designed to run without water and leaving your pump in this condition for extended amounts of time can burn your pump’s motor.
  • Low water flow and poor circulation – Since the water flow is intermittent then you’ll get poor circulation, and we all know what happens when there’s poor circulation. Your pool chemicals won’t be as efficient and there’s a chance of your pool water becoming cloudy or green!
  • Filter pressure problems – This is also attributed to the intermittent water-air-water that’s being pumped out. Without proper pressure, filtering of the pool water will suffer as well.

What causes pool pump surge and how to fix it

Air Leaks

The number one cause of pump surge or pulsing is your classic air leak. The more pressure your pump creates, the easier it is for air to get sucked through even the smallest leaks. And since air poses less resistance than water, it will get sucked by the pump instead of water, causing the pump to pulse.

How to spot Air leaks

Sometimes an air leak is so small that it’s almost imperceptible to the naked eye and it would be impossible to find without help especially since the air is being sucked INTO your pump. A good trick to spotting air leaks would be to smear some shaving cream on fittings or around your pump lid to see if any is getting sucked in.

Remember, air leaks are located BEFORE the pump, which causes air to be sucked into the pump and causes surge. Any leaks AFTER the pump will most likely leak out water because of the positive pressure.

Possible Air Leak Locations and How to Fix Them

Leaky pump lids – Your pump lid should be free of cracks and the O-ring must be smooth and undamaged for it to get a proper seal. Sometimes it’s just a case of some debris being caught in the lid and a good cleaning and re-greasing of the O-ring to fix the pulsing problem. If your lid is cracked or broken then you’ll need to replace it to prevent pulsing.

SEE ALSO: Broken Pool Pump: Replace or Repair?

  • Damaged fittings coming into the pump – When speaking of air leaks and pump surge, this is one of the more common culprits. It can be as simple as a loose fitting due to the pump’s vibration, which can be fixed by simply tightening the fitting, or if it’s cracked or damaged then a replacement is in order.

Low Water Levels

Low water levels can cause your pool pump to surge since the flow of water into your skimmer isn’t constant. The fix for this is simple, simply top off your pool with enough water to get to the required levels and your surge or pump pulsing problem should be fixed in no time. If you want to prevent this problem from happening completely then an investment in a water leveling device can ensure that your pool’s water level is at the right levels at all time.

Stuck Skimmer Weirs

Or as kids call it, that flappy door thingey on the side of the pool. Stuck or partially stuck skimmer weirs can also cause pool pump surge by preventing a constant flow of water into your skimmers. Check that your weir’s hinges are still swinging smoothly and replace doors that are cracked or stuck. Mr Pool Man has one of the widest collection of weir doors and parts available online so if you spot a broken weir door then you'll know where to go!

Clogged Suction Pipes

Now this cause is a little bit more complicated to diagnose and to clear. If the other possible causes have been ruled out then that only leaves you with clogged suction pipes. Clogged suction pipes can be caused by a lot of things, leaves, hairballs, dead bugs or even toys or tools that inadvertently fall into the skimmer boxes while the baskets are out (don’t laugh, it’s happened before). The most effective way to clear clogged suction pipes would be to use a drain king or a high pressure attachment at the front of the pool pump (the pump’s intake side) and blast the obstruction back out to the skimmer box where it can be collected and disposed of.
SEE ALSO: Maintaining your Pool with a Broken Pool Pump


Pool pump surge or pulsing can be pretty annoying and damaging so it’s best to get to the root cause of the problem before it damages your pump and causes any other problems. Luckily, the fixes are all DIY-friendly, so now that you’re armed with the knowledge of how to deal with it then it shouldn’t take more than a few minutes and a couple of spare parts to fully fix your pump surge problem.

If all of the issues listed above have been checked and you still have surge or pulsing, then try fully priming your pump again. For more information on how to prime your pump, check out our guide on how to install and prime your pool pump.
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1 comment

Big Fan

You’re a legend. I must have spent hours trying 15 different things, and the skimmer box flap was just stuck. Thanks a million!

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