When Should I Replace My Pool Filter O-Ring?

Changing out o-rings in your pool equipment can seem like a quick and easy task. And it is. Compared to other replacement parts, o-rings are rather inexpensive and are fairly easy to replace. However, failing to replace your o-ring can cause damage to other parts within your pool equipment resulting in a lot more spending.

O-rings and gaskets are typically made from an elastic-type rubber and are designed to seal, or in our case, help prevent water from entering in. O-rings are prevalent in most pool equipment including pumps, filters, chlorinators, valves, and heaters. Most pool owners know at some point they need to change the o-rings on their filter. However, most are unsure when and how often.

Filter Body O-ring
Filter Body O-ring

Pool filters may come with several different o-rings, but the one that tends to wear the most is the tank o-ring. The tank o-ring is the large round o-ring located between the filter head and filter body. It can be found in all three types of pool filters: sand, cartridge, and diatomaceous earth (D.E). Sand and D.E filters may have additional smaller bulkhead and valve o-rings which should also be changed routinely.

Pool owners tend to replace their filter o-ring once they notice water leaking down their tank. The only problem with waiting until you see the leak is the potential damage it can cause in the meantime. O-rings should be checked every time you replace your cartridge or grid elements and every time you clean your filter. It is never a bad idea to check other parts while your have a particular part open, whether a filter, pump, or chlorinator. Examine the o-ring for tears, rips, cracks, or any damage or defect that may compromise the seal.

Three Indicators of a Bad Seal

  1. Thoroughly Inspect Your Body O-ring

    The filter seems to leak when under pressure or when the filter is turned off.

  2. If your pump is losing pressure and you checked your pump for leaks. A faulty seal in your filter could be the culprit.
  3. An increase in water loss in an above ground pool.

All of these are signs that the filter o-ring may not be reliable anymore and we recommend you change it immediately

Once you purchase your new o-ring, there are a few steps you can take to prolong its life. O-rings should last several pool seasons with proper care. Be sure to examine the new o-ring before installing it. If you see any tears, rips, or anything that seemingly compromises the quality of the o-ring, do not install it and return for a replacement.

Aladdin Magic Lube
Aladdin Magic Lube

Also, use the proper lubrication for your o-ring. You should use Magic Lube II or another silicone-based lubricant, not Teflon. Teflon will dry out the rubber and eventually cause it to crack.

O-rings vary depending upon the make and model of the filter. If you need help identifying the correct o-ring for your filter, do not hesitate to give us a call at 877-372-6038. We’re always here to help!

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63 thoughts on “When Should I Replace My Pool Filter O-Ring?

  1. Hi Matthew. I recently purchased a poly group summer waves pool (15×42) It came with an SFX 1000 filter but ever since the beginning I’ve had issues with water spilling whenever the kids are in the pool- is that ‘normal?’ Also, my filter started leaking from underneath and I can’t seem to pin point the origin of the problem. I’ve taken it apart multiple time and the issue only grows. I haven’t been able to turn my pump on because of this. Please help!

  2. O ring looks fine but was told if you rub it and black come off on your fingers you should replace it…true or false? Tu

  3. I have a sta-rite DE filter/PUMP FOR A 27 FT diameter round pool. It’s 4 yr. Old. Recently I don’t seem to be able to get all the air out of the system no matter how long I leave the relief valve open, or how many times I stop and start the motor. I see no signs of leaks. Could I need to simply replace the big “o” ring that seal both halves of the DE filter together? I can’t imagine anywhere else If could be getting into the system. Could a stretched out O ri g be the cause?

  4. My pool water busted out of the D.E. filter running down the street the clasp around the tank was barely on so I didn’t know what to do I have an automatic pool filler but it seems like it won’t stop. I called one guy and he said just fill it up with a hose like everyone else. Then I called a leak detection company who said they can come out for 450.00.. which I thought was a bit too much.. I called another company and he asked had I checked the O ring I’m ordering it and should be here tomorrow.. I filled the water back up but running the pump it starts at like 15 psi when usually it runs normal on about 20 is there anything else I can do to try an fix the issue before spending an arm and leg??

    1. Going by your first sentence it sounds like you have pinpointed where the leak is coming from. I’m not sure what a leak detection company is going to tell you unless you suspect another leak. I would wait until you can test the filter o-ring to determine if that will mend the issue. And your pressure is likely low because apparently, you have a big leak sourcing from your filter.

  5. I have a leak in my pool filter. I have Hayward de filter. The water leaks and drips in drops from at the ring. You can see water dripping slowing from the screw. What is causing the leak?

    1. The answer is right in front of you; and by that I mean, you have to open the filter to find out. It could be a bad o-ring, cracked housing, the clamp isn’t tight enough.

  6. Good point Matthew, took the pump apart today and realized a crack along the pump housing by the intake. Intex however doesn’t show the part as replacement part. Must be replaceable only by purchasing a whole new pump. $$ is the issue that bothers me the most. I don’t want to buy a whole new sand filter/pump combo.

  7. I have an intex sand filter model number sf80110-1 my question is this, my pump is going on it’s second season and after pulling the filter out of storage and reassembling the prefilter housing now leaks where it connects to the pump. I never took the prefilter housing off for storage. Is it possible that the o rings are the culprit? I don’t see how water can even get outside the pump intake and prefilter housing unless the two o rings became squashed over winter. Please tell me your thoughts as I can purchase a o rings replacement kit but want to make sure that’s the issue. Thanks.

    1. I’m not familiar with the brand or model, but if there is an oring there, yes it could possibly be the issue. Or you may not have connected the hose tight enough. This is one of those cases where I could guess at things, but you’re going to get more done by breaking the system down and checking the pieces by hand.

  8. I have a pentair superflo pump 340038 and after i leave the pump filtering after 8-11hrs i notice bubbles in my pool and the pressure goes to 15-20p psi. Then i turn off my pump and the lid of the pump spits out water. Do think its the O- ring?

    1. What is the starting PSI for the filter? I need that to figure out how steeply it has risen in that period of time. Have you tried cleaning the cartridge?

      Also, have you checked the lid o-ring for cracks, pinches, or warping?

  9. I replaced my cartridge and now can’t seem to get a good seal on the housing. I went from a Porpoise C2412 to Pleatco PA120 Hayward CX1200RE Swimming Pool Filter C-8412 FC-1293 C1200. Not sure if the Pleatco is causing it or if I need to change the O ring. I’ve lived in the house for 5 years and not sure if it’s ever been replaced.

    1. I just had my pool opening and for several days now I find myself filling up the pool because I noticed that the water level is dropping couple of inches . Yesterday went to check pool equipment and noticed my pool guy left out the O ring for the pump out. Could this be the cause of my water problem ?

  10. I’ve replaced the O-ring on my above ground pool but still can’t get it stop leaking and another thing is there a big difference in the cartridge filters made from Mexico or Japan because the Japanese one would not run my vacuum the one made in Mexico would

    1. If the tank is still leaking, have you checked the that the clamp or tank is not warped?

      Also, the country or origin matters less than the design of the product. If you buy a shoddy brand, it could be made by the hands of Odin himself and it would still fall apart.

    1. First, what model filter do you have? Second, is the drain cap o-ring missing, warped or otherwise in disrepair? Third, is the drain cap broken or cross-threaded?

  11. Can you tell me if a worn O-ring at the tank separation of a PacFab ST50 DE filter would cause DE to return back to the pull at the return? Also should the metal clamp ends meet completely when closed? Thank you. Patti

    PS. my manifold and cartridges are brand new and installed properly,, no standpipe cracks or missing 0-ring at top

    1. I guess it would depend on where the Oring is on the separation tank. Generally, the issue would be with the separation tank bag ripping. If your separation tank is this Pac-Fab Stainless Steel model, then I don’t think the o-ring would cause a DE leak. A problem with the tank o-ring on that separation tank would cause a water leak, not a DE leak.

  12. I had my pool built last year. I have a company taking care of it for me and when they did a backwash they told me the o ring needed replacing at a $40 price on top of backwash price. That was backwash number 2 and their first.. i would not have thought the o ring needed replacing yet?

    1. If they are talking about replacing the main body tank o-ring this early, then yes it is rare for it to go so soon after being installed. If all they are doing is backwashing, I’m not sure how they would have seen that o-ring is bad unless there was a leak. Are you sure they are referring to the main tank o-ring and not the spider gasket in the multiport valve? Regardless, it is still really early for that gasket to go to, but more reasonable for that to have come across the problem.

  13. I have to add water to my pool about once a week. On average it drops about 2 inches. Also, when the hot tub is turned on, it will lower the water level in both the hot tub and pool. Recently the pool technician said we needed to have the 2 main pumps rebuilt, since there are small leaks on the main housing. Approximate cost is $30.
    Just wanting to make sure I’m getting the correct information and average price.

    1. The actual cost of the repair is dependant on what is actually being “rebuilt’ or replaced on the pump. Are they changing out the pump housings or just replacing bearings? The latter is not worth a $430 bill. Gaskets can be replaced by a handy homeowner, with the parts cost of about 30 to 40 dollars.

  14. I replaced my o ring and lubed ring and rim inside filter but i am unable to push filter top down to seal off filter. Is there an easier way to place filter top onto bottom where the o ring is stopping it from going on.

    1. It would help to know the model of your filter to give clearer instructions.

      Are you sure you purchased the correct o-ring for your filter? If you compare it to the old o-ring, does it appear thicker?

  15. Any trick to get the o ring into its place? The filter I have now, the o ring is really just one long piece (like the ring got cut, but was originally like that, I can’t get it back into its groove, so I can’t get the lock and the top back on

  16. I’ve had my above ground splash pool 15 years. Never had a problem with o ring. I took my filter out to wash it. It seems my o ring has expanded as its now bigger than the ring it should go on. Can that happen?

  17. All I need is one 5 inch o ring that goes under the cap/lid of where the cartridge is housed, the only ring is missing or lost after having pump emptied and stored for the Winter! I have asked for one ring, for gasket for pool pump, mine came with my intex steelframe 18′ by 9′ pool, it is a coleman. This seems like a simple thing to find,but I have been on my tablet and cannot find an o ring my pool is about 8 yaers old the part number is long gone it is so old the label on the filter pump is coming off i measure the opening where the other ring/gas get would fit, it is 5 inch diameter. HELP find!

  18. Whenever I vacuum my pool, all the green water goes back into the pool, what would cause it to do that?

  19. My tank has been leaking and I would say the O-rings need changing because it’s about 10 Years old, but today I did a back wash and now I’m getting sand in my chlorinator which is going into the pool. Is there anything else I need to replace? Please note we don’t have pool technicians in our area.

    1. You may have a cracked lateral or standpipe, or you may not have backwashed and rinsed thoroughly enough to clear the pipes before you returned to normal filtering. Also, there may be a spider gasket issue in your multiport valve.

      Is it a constant stream of sand or does it only happen immediately after you backwash? Does water flow from the backwash even when you’re in normal filter mode?

  20. Our pool technician told us that we needed to replace our O-ring. We told him to proceed but he didn’t do it right away. Now, a few weeks later, the large plastic filter housing has a large crack and the entire thing needs to be replaced. Do you think that waiting to replace the ring could have caused the break?

    1. The bad o-ring would not have caused the filter housing to crack.

      Did he assume the o-ring was bad because there was a leak or was the o-ring inspected? If the tech saw a leak but did not inspect the O-ring he may have just seen the beginnings of the tank cracking rather than a failed gasket.

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