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Why Is My Multiport Valve Leaking?

Leaking Pool Filter Valve

Multiport valves are the main water route interchange for your pool water. If the water needs to be forwarded, reversed or drained out, it will need to be done through this valve. The routing system inside a multiport valve is essentially water’s equivalent to chutes and ladders.

These valves have as many as seven “positions” but for the most part the average pool owner will only use a handful of these.  Here is a list and explanation of the most often used positions so we have a solid footing moving forward: 

  • Filter – The standard operation mode; the water is cycled from the pump through the filter media and back to the pool.
  • Backwash – This selection is the cleaning cycle. The flow of the water is brought in from the pump  then routed to enter the filter reverse to the normal direction. This effectively begins to loosen and eventually eject dirt through the waste port.
  • Rinse – Rinse returns the normal flow of water through the filter but it maintains the exit flow routed to the waste port.  After a backwash some particles may still be left in the pipes so to avoid that dirt being ushered to the pool, we need to rinse.Picture1

The Spider Gasket

If the valve is the highway interchange of your water then the spider gasket would be the guard rail. These gasket spokes act as dividers to ensure the path of the water stays true.  If your multiport valve has a drip coming from the waste port line, most pool technicians will jump for the spider gasket.

The spider gasket is located either on the diverter pinwheel or the base of the valve the diverter faces.  When we select a function on a multiport valve and release the handle, we drop the diverter onto the spider gasket.  If the gasket has become worn and warped then the water will seep through the seam and end up in the waste.

The Fix: The solution is pretty simple, replace the gasket. Some gasket replacements are simple, remove the valve cover and old gasket, then lube in a new one. Other gaskets are glued into the diverter which requires a few extra steps.  If you want a step by step guide on the different ways to replace a spider gasket read this: How to Replace a Spider Gasket on a Multiport Valve

The Diverter Spring

That tension we feel when spinning the selector handle is created by the diverter spring.  Besides making it hard to spin the handle, the spring serves the purpose of locking

Picture2the diverter against the spider gasket. If the spring in your valve is worn, it may be causing a seam between the diverter and gasket which shows itself in the form of a leak out the waste port.

The Fix: Replace spring, which to be honest, is not fun at all.  The spring is sandwiched on the diverter assembly which means it must be disassembled and assembled again. The hard part is getting the spring depressed enough to secure the handle pivot rod.  If you are feeling brave and want to attempt a spring replacement, please follow our guide: How To Replace a Pool Multiport Valve Spring

Valve Cover

The valve cover o-ring is found in the seam between the valve cover and main housing.  If water is found leaking from this seam then this gasket would be your culprit.  To access the gasket we would simply remove the 6 – 8 screws on the valve cover to remove it, peel out the o-ring, clean the groove, lube the new o-ring and re-attach screws.

The Fix: Read an inch above this line.

Valve to Filter Connection

Whether the valve is a top mount or a sidemount, it has to connect to the filter somehow.  At that joint connection there is a gasket holding on for dear life.  Because of the high flow at these connections, a blowout is somewhat common and easy to spot.

The Fix: Remove the valve from the filter and replace gaskets. Hopefully, the valve is piped in with unions so its removal is not a pain in the neck.  Once the valve is off, find the gasket and apply a freshly lubed replacement.

Thanks for skimming through our pool musings. If you have any further questions about pools, valves or otherwise, feel free to give us a call at 877-372-6038.

author avatar
Matthew Simmons Technical Writer & Pool Product Expert
Swimming pool expert at InyoPools and host of Poolside Chat, brings over a decade of experience in the pool industry.

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119 responses to “Why Is My Multiport Valve Leaking?”

  1. Mia Maniscalco Avatar

    Mathew, I was wondering if you could help me. Our pool company recommended we change the filter gasket since the pool vacuum was unable to get good suction. (We checked the hose for any tears and had the pool company try their vacuum and had the same issue.) so we purchased a gasket and after changing it there is water gushing out of the filter by the top where the handle is. We cannot run the pool now because the amount of water is so much. We took a before picture to make sure we lined everything up the same way when we put it back. Any help would be greatly appreciated.

    1. Matthew Simmons Avatar

      Mia,

      Did you replace the main tank gasket of the filter or a gasket on the valve? If there is water escaping from the multiport valve handle, you likely have an issue with the o-rings or washers on the diverter stem. Can you provide the part/model number of the multiport valve?

  2. Scott Avatar

    Thanks for reply. Yes I tried another gauge, same read exactly 10 psi. Will disassemble and check grids again for defects. Good suggestion checking waste port for leaks, will do that too.

  3. Scott Avatar

    I don’t have any visible leaks, but my filter pressure is not rising – it’s been fixed at 10 psi all season. Not normal. Also, some material I vacuum comes back in returns. Filter grids are new, so could it be bad multi-port valve?

    1. Matthew Simmons Avatar

      First thing, have you tried changing the pressure gauge? It may be reading a constant 10 psi because it is broken.

      The dirt showing up in your pool may be torn grids (even if new) or a manifold issue. The only way to know for sure is to take it apart to find the defects.

      The normal sign for a defective multiport valve is water where it should be i.e. flowing from the waste port when set on regular filter mode or from the valve housing itself.

  4. Btandy Avatar

    My filter is leaking where the multi port valve attaches to filter ball.pours out checked the o ring looks fine put lube on it put it back still leaking?

    1. Matthew Simmons Avatar

      Is the valve secured via a clamp, bolts or screwed on?

  5. Tatiana Perez Avatar

    The other day we tried draining some water from the pool now it won’t stop leaking/draining from the waste end. I don’t know if it got stuck on drain or if something else is wrong with it. We tried moving it to filter and even close and it keeps draining even when we unplug the whole thing

    1. Matthew Simmons Avatar

      Tatiana,
      I cover why that might be happening in the article, see the gasket or spring section.

  6. Marisa Avatar

    I have water leaking out the pipe that backwash water runs out of, when it is on filter it leaks bad out there we have to add water to our inground salt water pool twice a day

    1. Matthew Simmons Avatar

      If the valve handle is not too jiggly, it sounds like a bad spider gasket.

      Do you know the model number of your valve? I may be able to find you the correct replacement gasket.

      1. Nikki Avatar

        I have the same problem but my handle is jiggly what’s my issue

        1. Matthew Simmons Avatar

          Bad diverter spring, dislodged washer or broken stem. The only way to know for sure is to open it up.

    2. Elizabeth Avatar

      I have a brand new filter and pump, and having the same problem. Why is water running out of the waste port after the pump runs for a time and I’m trying to filter my pool to clear the water

      1. Matthew Simmons Avatar

        Read my comments on this post or read the article. I give several answers of varying length about what it could be.

  7. Liz Avatar

    Water is leaking from under the valve, it looks like its coming from where the valve and tank meet. Is this the regular gasket, o-ring or spider gasket?

    1. Matthew Simmons Avatar

      It sounds like you have a leak from the valve flange gasket. What is the model number of your valve and filter?

      1. Eric Avatar

        Hi Matthew, I’m having the same problem (valve leaking from underneath). I have a Hayward multi-port valve, model sp-715-a 50 that connects to a DE-6020 filter. it’s an older unit, and it looks like the new model # is SP0715XR50.

        1. Matthew Simmons Avatar

          Hello Eric,

          The original poster has a top mount sand filter, which is going to have a different configuration than your sidemount DE filter. Can you give more detail as to where, underneath? Like is it coming from the main body of the valve, underneath the valve cover(where the Backwash, Rinse, and Filter sticker is, or from the unions that attach to the tank?

  8. Chris Avatar

    I am getting small air bubbles blowing into the pool with the return water. Is this caused by a bad spider gasket?

    1. Matthew Simmons Avatar

      I know a blog a that answers this very question, take a look at it here: Why Do I Keep Getting Bubbles In My Jets?

  9. Sara Avatar

    My valve is only leaking when on “filter”, and by leak I mean it is flowing almost as much as when it is on backwash. It is air tight when on recirculate. Any suggestions on what component might be the culprit?

    1. Matthew Simmons Avatar

      The major culprits:

      1) Damaged spider gasket spoke, allowing water where it shouldn’t be.
      2) A loose/jiggly handle is a sign that the diverter spring is damaged. If the spring is broke the diverter will float and allow water to go where it pleases.

      The first thing to do is open up the multiport valve and find out what is the matter: How to Replace a Spider Gasket on a Multiport Valve How To Replace a Pool Multiport Valve Spring

      1. Ken Avatar

        I just purchase a new valve and gasket and it is very hard to go from rinse or backwash to filter, it is leaking by, in filter mode

        1. Matthew Simmons Avatar

          Because the valve is new, the diverter spring is going to be hard to compress. It should unstiffen over time. As for the leak, we covered that in the article, try opening the valve to see if the spider gasket is out of place.

      2.  Avatar

        I actually am having the same problem as Sarah. I recently had a broken lateral line, so we purchased a replacement lateral line assembly from you guys. It works, but like hers, the water is coming out of the waste/backwash port when it is on filter. I do notice the handle seems a little loose, but when you take out all the screws and take the head off then the handle is tight again. The gasket seems to be fine.

        Melissa

        1. Matthew Simmons Avatar

          On rare occasions, the spring can lose some of its stiffness. So, when your water pressure rises, the diverter will rise just enough to allow water out the wrong port. This is a problem that would only present itself when the valve is under pressure, and hard to test for.

          1. Melissa T Avatar

            I went ahead and purchased the whole top multi port . We put that on and it still leaks just as bad as it did with the old one. Any other suggestions?

    2. Luigi Rossi SA Avatar

      I had the same problem, even after replacing the spider twice!
      The culprit is a broken or collapsed side wall grove that holds the spider in place on the backwash sector. the spider gasket then cannot be held by both sides in its groove/position and thus during filter mode, water shushes through this into your backwash.
      Solution is to buy a new multi valve.

      1. Jason Avatar

        I found after replacing the valve 3 times that it was an issue with the water pressure in the pump causing the leak. I adjusted my inlet and outlet water and it works perfectly now.

        1. Ken Avatar

          Jason how were you able to adjust you inlet and outlet water. I also changed my valve 2 times and still I have the same problem of leaking.

        2.  Avatar

          How do you adjust pressure?

  10. Henry Avatar

    My valve leaks from the top under the handle.

    1. Matthew Simmons Avatar

      Hello Henry,

      Under the handle, on the stem of the diverter there are gaskets at the base of the spring that are meant to prevent such a leak. If your valve is leaking from under the handle the gaskets and/or spring are likely worn, or they are out of alignment. These guides should give you some more insight on how to disassemble and the location of the parts: How To Replace a Pool Multiport Valve Spring and How To Replace a Pool Multiport Valve Handle

      1. Sue A Avatar

        Hope I can post here about my own pump leaking from the hole under where the handle goes into the pump on the top of my Hayward DE filter pump….hope this is something I can fix myself?

        1. Matthew Simmons Avatar

          Can you clarify the location of the leak? I am little confused from the description.

      2. Sherri Avatar

        I have a triton multiport valve that is leaking water from where the handle attaches. Just had the spring, washers, o ring etc. replaced. Any idea why it’s leaking?

        1. Matthew Simmons Avatar

          There may be a crack in the cover? A replacement cover can be purchased (depending on the valve model number), but a key cover and handle assembly should fix the problem altogether.

        2. JR Avatar

          Pool is only losing water when running but nothing is leaking out that’s visible above ground . I do not have a waist line as my system is closed . ( I think ) my hot tub is draining back into pool but I believe check valve is problem . My pool has been off for a week with no loss of water including skimmers . I cannot see any bubbling above ground . In ground gunite pool .

          1. Matthew Simmons Avatar

            Unless I am missing something, it sounds like you have an underground leak. The issue may be somewhere on or around the skimmer as that is a pretty common problem area.

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