Leaking Pool Pump

Leaking Pool Pump

The first manufacturer to guarantee a leak-free pool pump is definitely going to corner the market.  Until that happens though, pumps will leak and pool owners will probably utter some choice words as they attempt to locate and troubleshoot the source.  Let’s review some of the most common leaks and how to address them.

Suction Side LeaksBlog Image - Pump Leaks (200 x 200)

On the suction side of the pump, any leaks will be air leaks.  This means air is being sucked into the system from some point between the skimmer and the impeller.  With this type of leak, you will commonly see air bubbles in the pump strainer basket and at the returns in the pool wall.

You might feel daunted by the task of troubleshooting the entire suction side but there are several likely problem areas to check first:

Pump Strainer LidBlog Image - Pump Lid and O-ring (200 x 200)

If not completely sealed, the strainer cover will allow air in.  With the pump on, slowly pour water over the lid.  If that decreases or eliminates air within the basket, you have found at least one leak.  You might be able to get by with just cleaning and lubricating the lid o-ring but if it looks worn or misshapen, it is best to replace it.  Also be sure to check the lid for any cracks.

Cracked PVC and Valves

Cracks in plumbing connections and valves are common sources of air leaks.  To test, you can try pouring water over these also.  Even if a valve is intact, it might still need a replacement seal.

Low Water LevelBlog Image - Water Level at Skimmer (200 x 200)

Probably the happiest cause of an air leak; this allows air to enter the skimmer but is easily addressed by adding water to the pool.  Also check for a stuck skimmer weir.

Strainer Basket Drain Plug

It’s small but this plug can let air in if the o-ring is bad.  Inspect it for wear and tear and replace if needed.

For visuals on troubleshooting suction side leaks, see our How to Identify & Correct Air Leaks guide and video.

Pressure Side Leaks

Any leaks on the pressure,or discharge, side of things will be water.  Since this part of the system is under pressure, water will be forced out any compromised area.  The pressure side is anything located after the pump strainer.  Signs of a problem are dripping or spraying at the discharge pipe fittings, water collecting underneath the pump, and reduced pool water level.

ImpellerBlog Image - Pump Cross Section (200 x 200)

The impeller spins on the motor shaft and creates water pressure.  If it gets damaged by lodged debris or simply worn from long use, the impeller can become the source of a water leak.  You will need to remove the motor from the wet end of the pump in order to inspect and replace the impeller.

Housing O-ring or Gasket

If water is leaking from where the the pump housing and motor meet, check for a worn seal here.  Should it need to be replaced, it’s a good idea to replace the diffuser o-ring at the same time.

Discharge Pipe

You can have a poorly sealed fitting on this pipe, or possibly PVC shrunken from heat.  If your schedule 40 pipe shrinks, a leak can form.  To repair this and prevent it from happening again, try using schedule 80 pipe nipples on the suction and discharge.  Schedule 80 is heavier duty and will stand up to heat better.

Pump HousingBlog Image - Pump Housing (200 x 200)

Cracks can develop in the pump strainer housing.  Some try to repair hairline cracks but I have not heard of too many success stories over the years.  It might be time to replace the housing, if the pump is fairly new, or consider a whole new pump.

Shaft Seal Leak

Between the pump motor and impeller is the all-important shaft seal that keeps water out of the motor.  A leak here is a common cause of motor failure so it’s crucial to address quickly.  Some signs are water coming from behind the seal plate and collecting underneath the pump where the motor and wet end meet.  You might also hear some abnormal pump noises; this comes from the bearings as water gets inside the motor.Blog Image - Shaft Seal in Motor (200 x 200)

A common cause of this leak is replacing the motor but failing to replace the shaft seal at the same time.  Reusing the old seal is a bad idea, as seals warp over time and will likely not mate properly with the new motor.

The advice here is simple – replace the shaft seal.  If a tune-up kit is available for your particular pump make and model, it is the perfect time to also replace o-rings and gaskets while you have the whole pump apart.

If checking all of the above fails to locate and troubleshoot your pool leak, it could be in the underground plumbing.  Checking this will depend upon your level of proficiency and how accessible those lines are.  As much as I hate to say it to any and all with DIY hearts, it might require the help of a pool professional and a dip into your pool bankroll.

21 thoughts on “Leaking Pool Pump

  1. I’m afraid I’ve ruined my pool plumbing. I turned the engine off, but forgot to turn the handle from “filter” to “closed” before I opened the pump basket. Cloudy water filled. I replaced lid, and turned handle to “closed.” I waited a few minutes. Cloudy water (DEH leftovers) shot into my pool and turned it cloudy. (Least of worries right now). I turned handle to filter, cloudy (DEA residue maybe) water shot out. Heartbreaking part is that my plumbling that has been just replaced in leaking at every connection, even near the motor. Did I ruin it? Thanks for any input.

    1. I’m sorry but I do not understand the DEH and DEA acronyms. Can you explain them?

      Cloudy water usually is not a difficult issue to deal with and not normally a plumbing issue. Use a clarifier or floc and vac to clear it up.

  2. Hi Matthew,
    I have a slow leak under the pump basket and can’t see where it’s coming from. It’s not coming from the lid and doesn’t look like it’s coming from the drain plug. It started after I emptied the skimmer basket this week. Is there any test I can perform to see if the unit is cracked or where the leak might be?
    Another thing to note is that once the pump shuts off and it sits for several hours, there is air in the basket.

    1. I do not have much of a trick for this particular problem. The best this I would recommend is to let your pump pad dry, then start it up. Hopefully, you can trace where the leak is coming from easier on the dry pad. or you can remove the motor and basket from the housing to determine if you can inspect the inside of the pump housing for cracks.

    1. Is this on an above ground or inground pool suction line?

      Try the moke trick to find any hard to find air leaks. Use incense or cigarette smoke to find any sucking air leaks. Wave the smoke around the pipes in question, the smoke should be pulled into the offending leak.

  3. Hi there,
    Just installed an “new to me” pump in my system. However, when I turn on the pump, water begins to comes up from the fitting that has my discharge pipe (flex pvc) which goes to my sand filter. I’ve tried retreading with teflon tape, I’ve tried loosening it, tightening it (should I be tightening only hand tight?).

    Any ideas on how I can fix this? The leak is quite bad.

  4. You seem to be quite responsive which is great, so I’ll give it a shot – I have a jandy pump with a leak between the inlet coupler and the pump. The O-ring is in tact, but when I unscrewed the coupler I noticed the pump and the PVC pipe weren’t exactly flush. Does the coupler when tightened make them flush, in which case I probably have a cracked thread, or is there something bigger that would require repositioning the pump?

    If it’s a cracked thread, is there a way to fix that without replacing the coupler entirely?

    1. If the pump wasn’t leaking, then all of a sudden it is, and in the interim, you haven’t fiddled with the union any, I would say it could be a crack. But instead of hypotheticals from me, I would take a look at the actual port.

      Regarding a fix, you can use stuff like JB Weld to mend a crack. But if it is severe, you may need to bite the bullet and get a new housing.

  5. I’m troubleshooting the pressure in the pool filter getting too high. I have a drip water leak coming out of the tension control clamp of my FNSP60 pool filter. I just replaced the complete element grid assembly and am still having high pressure. Do you think replacing the tank clamp o-ring would fix the leak? What are your suggestions?

  6. I had a leak at the discharge side of my pump. Replaced the pipe (leak was at the coupling that comes directly out of pump top). Cleaned filter, lubed o ring at valve attached to the pipe, replaced drain basket and o ring (lubed it as well). When I started the pump back up, after filling it with water, there was no pressure going to the filter. You can feel water moving through the pipes and no leaks seen with soapy water or smoke.
    Checked slimmer basket and all jets and can’t find any issue. Any other suggestions???

    1. Does your filter have an air relief valve? This valve will release any trapped air in your system which can restrict flow. The air relief should be used after each time you open the pump, filter or chlorinator.

      1. The filter is a Hayward Starclear Plus, the valve has limited air flow. You can feel a trickle of air from it, but no spray of water like when typically open and pressurized. I recently replaced the pressure gauge just to make sure that wasn’t the problem

  7. I have a leak between at the impeller joint on Hayward pump, where it;’s held together with a big (15″ maybe) tension collar band. Is this just a bad O ring? Something else?

  8. I have high pressure around 30 psi when water flow directed to spa that spills over into pool. When only directed into pool psi drops to 10. We also have 2 jets in the spa that seem to have little to no flow. We ran the hose and water does flow. We replaced our DE filter and now we noticed a new leak around the pool pump. We replaced the o rings and now water shooting from housing. Did the high pressure crack the pump or is the pump causing the whole pressure problem? Pump is an max-e-pro installed in 2015.

  9. Matthew-
    Thanks for the reply
    The label says
    “Pump Model Number
    PE 5E- ????? ( illegible)
    Made in USA A87F”

    My guess is it’s 25+ years old.

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