8 Answers to “Why Is My Pool Pump Not Working?”

As pool technicians, we hear these everyday:

“My pump is on but the water is not moving.”

“Why is there water leaking from under my pump?

“Why is my pump losing its prime?”

And the classic but vague, “My pump isn’t working, what’s wrong with it?”All these and many others are signs of a failing pool pump but the source of the fault varies. The key to diagnosing the pump is understanding its parts’ functions and what happens when a certain part is failing. Knowing what to look for allows you as a homeowner to identify and fix the problem yourself, thereby saving money. Or if you’re not up for the job, be able to explain the issue to a pool technician so they can fix your pump. Most importantly, being educated on your pump prevents you from being pushed into buying unnecessary parts by your Poolman.

We’ll do a rundown of the 8 most replaced parts on a pool pump with an explanation of each part’s function and the symptoms of a possible issue.

1.) Motor


  • Grinding or Screeching – A sign of bad bearings caused by age or rusting. Bad bearings are also a sign of a leaky shaft seal.
  • Loud Hum – If the shaft is spinning then it is likely the capacitor failing. If the shaft is not spinning then the bearings have frozen and locked up the shaft.
  • Flipping Breaker- A deep internal component within the motor has failed and requires the motor to be replaced or rebuilt.
  • Silence – The shaft of the motor has frozen providing you with a new 30-pound paperweight. There is no chance of rebuilding the motor, the only route is to replace.

A pump’s motor is the heart of your pool. Put simply, if it’s not a pumping then you’ll be a slumpin’. Generally, motors have a lifespan of 3 – 5 years. The life of a motor can vary greatly upon the conditions it endures in its application. A motor exposed to the summer sun, spring rain and early fall freeze will likely burn out quicker than a sheltered one. If you’re concerned about weather effects, we suggest using the Universal Motor Cover to protect your investment.

The Fix: How To Replace the Motor on Your Pool Pump, How To Wire A Pool Pump,

2.) Seal Plate


  • Obvious wear and tear, i.e. cracks

The seal plate is the joining point of the motor and the pump housing. Damage to the seal plate is usually caused by an over-tightening of either the motor or housing bolts. Excess tightening will cause cracks in the frame and eventually form leaks.

The Fix: Replace Seal Plate

3.) Gaskets & Seals

When someone says they are seeing wet cement on their pump pad, the usual cause is a bad gasket, shaft seal or o-ring. These rubber parts seal the joints of your pump making it watertight. Each seal failure will affect your pump in a distinct way. If your pump requires multiple gaskets replaced, we suggest applying a Gasket and O-ring Kit (GOKIT) if available. We also have a guide on installing a gasket kit:  How To Use a Tune up / GO-KIT

Shaft Seal


  • Water dripping from motor vents
  • Loud bearings
  • Rusty motor casing
  • White whirling on motor face

Arguably the most vital and sensitive of the bunch, this $12 – 20 part is the last line of defense protecting your $200 electric motor. And I shouldn’t have to tell you but water and electric motors do not get along very well. The seal consists of two sides: a white ceramic ring sleeved in a rubber protector and a spring-loaded side with a carbon ring. If your shaft seal begins to fail, water will leak into the motor casing. This small leak will begin the process of corroding bearings, copper windings or electrical components. Friendly reminder, whenever replacing a motor always replace this seal.

The Fix: How To Replace a Pool Motor Shaft Seal

Housing Gasket


  • Wet pump pad
  • A leak coming from the seal plate and housing seam

The largest of the gaskets acts as the seal between the seal plate and pump housing. Diagnosing a faulty housing gasket is easy due to its location. If water is spilling from the large seam between the pump seal plate, then this would be your culprit.

The Fix: How To Replace Pool Pump Gaskets

Lid Gasket


  • Large air bubbles in the strainer basket
  • Low water pressure
  • Takes longer to prime pump

“Why am I getting air in my system?” The answer to that question always begins with checking the lid o-ring of the pump. Unlike the other gaskets on the list, a bad lid gasket causes a sucking leak rather than a blowout. The usual sign of a bad lid o-ring is larger than normal bubbles in the strainer compartment. The air leak may also cause a hissing sound.

The Fix: How To Replace Pool Pump Gaskets

Diffuser Gasket


  • Losing prime
  • Low water pressure

This important but sometimes forgotten part, the diffuser, and its gasket enhance the pulling power of the motor and impeller, enabling the pump to prime itself. Located at the tip of the diffuser, the gasket seals the diffuser/impeller assembly to the front part of the housing. The funnel-like diffuser is then able to focus the impeller’s pulling energy, increasing its strength. This aids in priming and maintaining water pressure.

The Fix: How To Replace Pool Pump Gaskets 

4.) Impeller


  • Losing prime
  • Low water pressure

The motor may do all the spinning, but the impeller does all the work. Found screwed onto the end of the motor shaft, the impeller is a vented or veined disk. These veins act as a boat propeller would, drawing in and then pushing out the water. If your impeller is broken then you will see little to no flow of water. There may be rattling as well caused by broken pieces of the impeller within the housing.

The Fix: How To Replace A Pool Pump Impeller

5.) Diffuser


  • Low pressure
  • Loss of prime

The diffuser is a cone-like shroud that sits over the impeller. Its main function is to focus the impeller’s pulling force towards the pool to enhance the water draw. A broken or cracked diffuser will have cracks that siphon off the impeller’s pull, lowering water pressure.

The Fix: How To Replace A Pool Pump Diffuser

6.) Strainer Lid


  • Large air bubbles
  • Obvious or hairline cracks
  • Warping

The strainer lid is the main visual inspection point of your pump. Or in simpler terms, it’s where you check to see your pump is running. Lids become brittle with age and can break or warp from excessive sunlight.  Hairline cracks in a cover can create a sucking air leak allowing air to slow your system.

The Fix: Replace Strainer Lid

7.) Strainer Basket


  • Rattling noise within strainer basket
  • Clogged impeller
  • Torn or damaged cartridges

The strainer basket catches debris before it reaches the guts of the pump. A broken basket can harm your pump or filter because it misses debris that can damage the impeller, diffuser or filter cartridges.

The Fix: Replace Strainer Basket

8.) Housing


  • Dry rot
  • Cracks forming near ports or bolt holes
  • Obvious wear and tear

Considered the hull of the pump, a housing encases all of the above parts. A pump housing failure is usually seen coming because of the obvious long-term degradation of the pump. The sun is usually the biggest culprit when it comes to housing damage. The pump getting baked during the summer months will cause the housing to start petrifying and becoming brittle. Cracks will begin to show around the stress points. The housing is the second most expensive part on a pump to replace, only behind the motor. If the housing and a few other parts need replacing, it may be best to replace the whole pump. Read our previous blog on determining what to do in this case: Pump or Motor: To replace or not to replace… That is the question.

154 thoughts on “8 Answers to “Why Is My Pool Pump Not Working?”

  1. I have this Pentair intellipro variable speed pump, and it stopped working this morning. There is power but no water flow. It’s been cold here in Florida the past nights and I covered the pipes yesterday with towels. What should I do? Thanks!!

  2. My pump works for about a minute than it’s still running and I loose all pressure. Than it like reprime itself for about a minute. At this time everything is working good and than it looses all pressure again. And this just steady repeats itself. When it looses pressure the pump seems to sound the same.

    1. There may be a sucking air leak on the suction side of your plumbing (the pipe before the pump.) The areas of concern pump lid o-ring, diverter valves, joint seams and vacuum hoses.

      Everything except the vacuum hose can be checked using the smoke trick. Wave a lit cigarette or incense stick along the length of the suction side pipe. If there is a leak the smoke will be drawn in.

      For the vacuum hose, take a section of hose, seal each end with tape, then submerge in water. If you see air bubbles from the body of the hose, replace that length of hose.

      Read this article for more information: How To Determine Why a Pool Pump Won’t Prime

  3. I have a salt water pool with a spa where the pump is located. When the pump came on it used to rise about 6″ above the surface of the water. Now it just about makes to the surface. All I see is the water pouring up. I keep the filter clean but that doesn’t help. I been seeing some black dirt spots on the bottom of my pool lately which I vacuum out. I don’t know where the dirt is coming from. Could this have something to do with my problem? Could the dirt be getting into the system and interfering with the pump coming up the way it use to?

  4. My pump seems to be losing its prime after 4-5 days runs on a timer works fine then gets air bound.there is no air in pump once running and system is very quiet.flushed out line from pump to strainer it’s clear ,checked seal on pump cover all tight also checked gasket in union all good.any taughts

    1. In that interval of 4-5 days, is your water dropping below proper levels? It could be natural evaporation or a water leak in this case. Another cause of low water is a leak from a multiport valve waste port.

  5. I have an Intelliflo VS Pump model 3050, 3.0 HP and I’m running it with an electric generator because we just went thru hurricane Maria and the screen is reading ” Alarm Over Voltage”.
    Do you think the motor is damage? I’m trying to reset it and it’s not working. My son bought it thru EBay and sent it to me. Help

  6. I have a question. My Mom’s pool pump is only 1.5 years old but the other day it made a loud bang like a firecracker, then it just stopped for good. The local pool company sold her a new capacitor as that is the most common cause of a pump not starting, however, I can’t imagine a capacitor making a giant bang when it stops working, so either they simply don’t listen to their customers or they sell them things they don’t need. They kept her original working capacitor. Pinch-a-Penny sucks. Anyways, when we turn it on there is zero sound at all. My guess is the entire motor is blown.

    I suppose electrical issues could make a loud bang, but she didn’t see any smoke afterwards so I’m thinking dead motor. Any suggestions?

  7. What would cause a pump to lose some, but not all, of it’s suction over a 12 hour period? Here’s my setup: I have a 1 hp Flotec motor/pump driving a Hayward Navigator Pro pool cleaner, attached via the skimmer. I know the suction level is a tad low for the Hayward, but it has worked just fine for several weeks, scooting all around the bottom of the pool without issue. I usually run the pump for 8 hours a day, but I just ran it 3 days straight while adjusting chemicals and clearing cloudy water after a big storm (Irma). However, this morning the Hayward is no longer moving about the pool. The pump is still running, water is still flowing out of the returns, but the suction level is noticeably lower. That explains why the Hayward isn’t moving. There are no water leaks near the motor/pump, there are no inlet air leaks, the pump skimmer basket is clean, the cartridge filter was cleaned out yesterday, and the pressure gauge on top of the filter looks good too. The noise of the motor/pump is the same as it’s always been. Is it possible for a pump to slowly lose suction?

    1. Here are a few guides you might want to use to troubleshoot the problem. You should also check the cleaner hose line for any pin hole leaks. These tiny leaks slowly pull in air causing the gradual loss of suction you are describing. Seal each hose length with tape or something else and submerge the hose in the pool. If there are air bubbles coming from anywhere other than the ends, then you have a problem.

      How To Determine Why a Pool Pump Won’t Prime
      How To Prime a Pool Pump

  8. Matthew,
    My la01n booster quit working. The shaft at the back spins freely, I took the impeller/front off and it spins and is free moving. I replaced the capacitor on top. When electricity is applied, the shaft spins., the motor hums for about 5 seconds and then the whole thing shuts off. What do you think is wrong? Thanks.

    1. You may have two: a run capacitor and a start capacitor. Some motor have a governor at the electrical end of the shaft. Check that it is not stuck open. If your capacitor(s) and governor are good and the motor shaft rotates easily you probably have a burned out motor coil and you will need to repair or replace the motor.

  9. my filter gasket lid keeps making a sucking effect when the filter is turned on. when it is off the water begins to leak from the top of the lid. I made sure to seal the lid with magic lube from a pool store, however, this is still occurring.

      1. Do you mean it is making a sucking sound? if so, is it s sucking sound for water or air? Does your system lose prime?

        Intex is not always known for their quality, so I wouldn’t totally discard a faulty gasket as the cause. If you can get one for cheap or free for from the dealer you bought it from, I would give it a try.

  10. No it didn’t trip a breaker…it doesn’t make any different noises it just clicks when it goes off….

  11. I have a small above
    Ground pool the pump was working fine but then it started kicking off after a minute of running. I have tried everything that I know from changing plug ins to cleaning everything and still can’t seem to get it to run for 1-2 minutes then it shuts off. What else am I missing or is the pump burned up…when it runs it does good.

    1. It could be a lot of things, we would need more info on it. Did it trip the breaker? Have you tried turning it back on? If so, what happened (or didn’t happen)?Was the motor making any noises before it suddenly stopped? If so, what were said noises?

  12. I was emptying my green pool using my pump on waste mode. It emptied 95% of the pool water and then although the pump is working but it is not pumping out any waster water out of the pool. What could be the reasons and how can I fix it?

    1. Because the water level is significantly lower, the pump now has to pull the water from a deeper point. If you have a smaller pump, the added feet of vertical rise is too much for it to stay primed. Buy a sump pump.

  13. I was vacuuming my pool yesterday and the pump was running fine. For some strange reason, last night I noticed that the pump wasn’t sucking in water from the pool with full power. Is it possible I clogged something? I cleaned out the filter after I vacuumed too. I even cleaned out all the strainers. Could the pump just be overworked? I just bought this one in May brand new.

    1. This may as simple as an air leak, or a clog. The air leak is the quickest thing to check; use incense stick smoke to find the source of an air leak. Light the stick, then run it along the suction-side pipe and pump; is there is a leak then the smoke will be pulled in.

      Clogs are a little bit harder, get a pipe snake to try fishing out any pipe debris.

  14. My “less than a year old” variable speed pump is making a grinding nopise like it has striped gears. just started this and won’t prime at all. the noise is really loud. i am leaving it off.

    1. Ok, well have you opened the pump to check if there is anything stuck in the impeller? Can you tell if the pump is leaking? i.e. the pump pad is wet though there is no rain?

      The sound could be a bad bearing, which is covered under most warranties (as long as it was not caused by an installation error.) Contact the dealer from where you bought the motor, to find out the warranty procedure.

  15. My pump seems to be running fine , has a good pressure and blows out just fine but doesn’t seem to be filtering and the suction isn’t quite as strong but does blow out the return with plenty of force. I leave mine running all the time to keep the metal from my well water filtered out. Well it would not clear and stayed a very light green for the last three weeks like it wasn’t filtering correctly, so last night I turned off the pump for the night and it’s is a dark brown today like maybe something trapped in the filter came back into the pool as I had not added any water or clorine, it just seemed to not be filtering out correctly because when I backwash it was not pulling the metal color water from the filter. It doesn’t seem to have any air leaks but the suction it’s as strong as usual. I changed the sand in the filter this year as I do about every 2 to 3 years because of my heavy metal problems. Terri

  16. My pump won’t turn on. It is a Polygroup that is only one yr old?! Any ideas what is going on with this? I also have a friend who has a polygroup pump, again 1 yr old and won’t turn on. It isn’t the main plug…I am stumpped and frustrated with the kids wanting to swim in this hot weather 😥

  17. I have the same issue with the pump on my sand filter. It was on running fine when I left the house yesterday, but was not running when I returned, even though the switch was “on”. I checked the electrical box and the breakers hadn’t tripped. Does this mean the motor on the pump died? I already have a back up pump on hand in case I need to replace.

      1. Could you please tell me why my pool sand pump will only work for 2 hours and then it will have to be back washed again and again and will only work for two hours consistently? Thanks.

  18. I cleaned the filter on my pool. The pump turned on and I left. I can back 5 hours later and 5he pump is off and not turning on.

    1. We will need more information than that to troubleshoot the motor. Has the breaker flipped? Was the pump running dry? If this was a sand or DE filter, did you release the air from the system?

      If you did not, the air bubbles in the plumbing can prevent the pump from priming, allowing it to run dry, and overheating the motor.

  19. I am new to pools and I got a new filter and pump put in. It was working fine until the rain started coming down. now it seems like the pump isn’t working correctly? Could it be too much water in the pool? Please help.

    1. Can you be more specific when you say “it seems like it is isn’t working correctly.” What exactly is the pump doing?

      Also, too much water in a pool is not going to affect the pump. But too little water will.

      1. My handle turns correctly, but just won’t backwash. All others work. Rinse, recirculate, waste, filter. Just the backwash does not pump out water.

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