Leaking Pool Filter Valve

Why Is My Multiport Valve Leaking?

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

click here to find your replacement pool filter valve parts

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.

click here to find your replacement pool filter valve parts

119 thoughts on “Why Is My Multiport Valve Leaking?

  1. A mouse got in through my waste pvc pipe and chewed a tiny piece of the spider gasket. The local pool company says they don’t replace just the gasket due to issues with the glue and want to replace the entire multi port. I was planning to add a valve to the pvc waste line to keep the mouse out in the future. Could this valve also solve the leak issue since while the valve is closed the water can’t escape? I don’t have any leakage in recirculating mode, just in filtration mode (which is adjacent to the chewed bit).

    1. For anyone reading this in the future, I tried this approach and the water was diverted into the site glass which blew off. At least the shutoff valve will prevent the mouse from getting back in there.

  2. I a Pentair Quad DE 60 filter and have lived in this house for 7 years now . This year I’m having trouble w the water being cloudy despite perfect chemistry, cleaned cartridges and new DE, frequent backwashes and DE replacement. I’m wondering if I have a DE leak somewhere in the system. And I happened to notice that my multi port valve is a SM10-3 SAND (USE ON SAND FILTER ONLY!) I guess the previous owner forgot to change it to a DE compatible multi port valve when they changed to DE filter? … but it seems like it’s been working fine for past 6-7 years. I guess my question is, can this mismatch cause a DE leak, and perhaps a delayed one like I’m getting now? Should I replace it w the correct multi port regarhdless? I’m going to go ahead and replace my DE cartridges since they are 7+ years old and could be a cause of water cloudiness if they’re not running efficiently or have a hidden leak causing DE to escape. Thanks for any help/advice

    1. The mismatched valve wouldn’t be a factor in your case just because though it may say “sand only,” it can be used on DE filters as long as the In and Out port measurements and orientation match up, the valve should work as required. And as you mentioned, it had been working for years, so this blip should have happened a long time ago if it was an issue.

      While the pump is running, I would put my hand down by the return to see if there is a noticeable spray of DE in the returning water. Is there water flowing from your backwash pipe when the valve is set to normal filtering? If it is leaking water, then that could be a sign of a corrupted spider gasket or diverter spring. Check the handle; if it is jiggly, the diverter spring is not operating as it should.

      A bad combination of pool chemicals can also cause milky/hazy water. I know you said the chemistry is perfect, but it never hurts to double-check. Bad combos: High pH + High Calcium, High pH+ Low Chlorine, Low Chlorine + Low Stabilizer (CYA)

  3. When I backwash, then rinse then turn back to filter the water continues to trickle out the waste port. Sometimes if I pull up on the handle hard it won’t leak. I don’t know if that has anything to do with it not leaking or is a coincidence. What do you think it could be?

  4. I had water leaking form the waste line. I replaced all the gaskets and the spring. There is still water leaking from the waste line. I do not detect any broken grooves in the spider gasket. Thoughts?

  5. I have a leak through the waste port as well as at the coller where the multiport connects to the filter housing. I had neither issue last year when closing. It’s odd that the the spider gasket and the oring gasket at the bottom both whent the same year, right? I don’t want to purchase the gaskets if I need to replace the entire multiport… Thoughts?

  6. My pool services guy told me I have too replace the whole Hayward top. When filtration is on it leaks like a stream down the grey system. Is this true or do I just need a new valve.

    1. I am going to presume the “grey system” is referring to the waste line. So that could be a few things that I mention in the article, the spring, diverter steam, spider gasket. You should take a look at it yourself or have them explain exactly what was wrong with it.

  7. HiI have a multiport and have put it in the Recirculate mode and after 2-3 hours I have lost 2-3″ 1/2 tile of water out of the Pool , why is that happening?

  8. Pool still drains after the valve is in FILTER position. Pool built in 2009, only upgrades are the pump & heater. I shut off the main power.

  9. My pool won’t prime, someone told me that my multiport was defective and that is the reason because some water was coming out of backwash when it was in circulate mode.
    The pool was working fine when I opened it
    But I was backwashing an awful lot due to how dirty pool was then it started losing prime when I would turn pump off. So I would reprime every time to turn on. Then it completely stopped priming at all. That’s where I’m at now. Do you believe the multiport needs to be replaced. Thank you

  10. Need help with a leaking Jandy 3 port valve in the suction line. When the pool is turned on the leaking stops but it sucking in air. The issue is that I can’t just replace it. The pool is built 3 feet above where all the equipment is and there is not shutoff to the suction lines. The skimmer and main drain lines go directly to this diverter so if I try and replace it the water gushes all over the place. I’m planning on having a professional replace all of them in the fall when I close the pool but for now I’m just looking for a quick and easy (affordable) fix to this so that we can use the pool for the next 2 1/2 months which is how long summer lasts in New England. The leaking is from where the top of the diverter is screwed into the base. Any ideas or suggestions?

  11. Hi We have had our above ground pool for 20 years. We always take the valve cover off for the winter and put it back on in the spring with no issues. We just purchase a brand new filter and valve, 19 in Blue Devil. It is leaking between the valve cover and tank. We have taken the top off twice and made sure the gasket is in place. The second time we did this it did not leak for hours and then it started leaking heavily at the side gaps of the flange. We can not figure out what we are doing wrong. This flange does not come completely together like our old flange and we are afraid to keep tightening that we may damage it. Any input is greatly appreciated.

    1. If this filter is brand new and it is already leaking then you have a defective unit. Contact the company from you purchased the filter to have them replace it immediately.

    2. I’m guessing it’s not as likely with the newer filters, but found on my previous, older filter that even though the filter cover COULD physically be put back on without any specific position/alignment to the base and wouldn’t leak normally wouldn’t leak, upon closer inspection I discovered that there actually WAS a very slight notch/slot in the cover that needed to be aligned to the bottom,base flange to ensure the cover and flange met completely together, with no leakage, but when it DID started leaking slightly once again, several months later, after checking seals, etc… I finally noticed, then, that there was a nearly invisible fine, hairline crack on the inside wall of the lower/bass piece… Good luck!

  12. I have all original equipment since my inground pool was built in 2006. The pool company came to open the pool this week. I was out there talking with them much of the time. When I was asking questions they were rude. They said they knew what they were doing. I told them that I needed to know what they were doing since I keep a log of all things related to my pool in a notebook. I left for a bit and when I came back they handed me the pressure gauge. They told me it was stuck at 10 and it was broken. They replaced it with a cheap plastic one. I noticed right away the new one was leaking! I told them I never had any leaks at the pressure gauge. They did not ask my permission before they replaced the pressure gauge. If they would have asked me I would have told them that it sticks at 10 when the pump is shut off, but it always registered the proper pressure, i.e. 20, when the pool was running. Then they applied some white stuff and told me it would “cure” Well the leak went from dripping to a steady stream. They told me there is a crack next to the pressure gauge. I believe they broke it when they wrenched off the “bad” pressure gauge that had been there since 2006. I am so pissed! Now I need to get an entire new multi-port!!! What do I do? Do I take them to small claims if they refuse to fix what they broke? They knew I was right inside the house and they still didn’t try to reach me via text or come to the back door to show me what they were replacing. If they had, I would have known exactly how this new leak happened. I am livid!

  13. When I move the multiport to backwash losing water from the filter which starts to fill when pump is switched on. Multiport lid contains a built in gasket which looks fine. Also can hear gushing sound in multiport when on filtration . Any ideas on cause

    1. Check the diverter spring. If the diverter spring is broken or displaced the diverter can lose its seal, allowing water to flow through the backwash. A sign the spring is loose is a jiggly handle.

  14. Hi, I just installed a new TR60 sand filter and also a new Hayward HP 1.5 single speed pump. The problem I have is that the laterals in the sand filter keep on breaking and I have a lot of sand in the pool …. I have had to replace the broken laterals already 4 times and every 2 weeks one or two break ….. I have no idea what can be wrong for the laterals to break? Can it be that the multi vale is not working properly? This is the only part I haven’t replaced… Or do I put too much sand in the sand filter? Any help would be highly appreciated. Best regards, Philip

    1. A multiport valve is not going to cause laterals to break. I would look into how you are installing the laterals. One of the most vulnerable times for a lateral is when you are adding sand to the tank. That is why we suggest filling the tank halfway with water to the laterals do not take the full brunt of the weight as sand is poured in.

  15. I’m not entirely sure how, but the pin on our Hayward Multiport Valve came out on one side and now the valve can’t sit where it’s supposed. Getting the pin back in is proving to be a pain, though! I’m having difficulty getting it to line up to be able to go through. When I noticed the valve wasn’t seat properly and the water level in the pool was dropping, I turned the pump off. Since turning the pump off, however, the water level has dropped all the way below the skimmer level. Could water still be draining out even tho the pump is off?

  16. Hi, I have just installed a brand new vari-flo SPO714T over top of my Filter (S244T) and when setting the dial into the preset groove for “backwash” it doesnt work (no water flows out). However when i push down on the handle and move it slightly more clockwise (out of the grooved position) it works fine.
    Is this an issue with the spider gasket? Faulty Valve?

  17. I have water coming out the backwash port while on filter and when on backwash the jet is blowing in the pool. We have replaced the spider gasket and looked at the lateral assembly nothing wrong there and of course we chamged out the sand.

    1. Is the valve handle jiggly? Like the article mentions, if the spring is old it will begin to give. The loose spring allows the diverter to shift up pushing water out where it shouldn’t be, like your backwash port.

  18. I am adding water to my pool 2 times a week. No visible leaks around pool. Could the multi port valve (Jandy) with sand filter be leaking internally and how can I verify that?

  19. My variflow is leaking from the bottom pipe that commects to the filter tank. Is there a gasket where that pipe goes into the variflow housing? Its leaking from the section that goes into the variflow housing.

  20. Please help. I have a few questions. What if we don’t rinse after backwash? Could that be the reason water is pouring out the drain while on filter? Also, does it matter which direction (clockwise , counterclockwise) I turn the latch to switch modes?

    1. Also, does it matter the precise level of water in the pool? If it’s too full will it drain on filter mode?

      1. Question, why wouldn’t you rinse when you backwash your filter? Also, have you opened the valve to check the spider gasket or diverter spring as the article suggests? If not, I would start there.

        Yes, it does matter how the handle is turned. You should only turn it one way if you take turns going clockwise and counterclockwise there is a higher chance of the gasket getting stretched or pulled out of place.

  21. I have an Sand Dollar SD-40 with 1.5″ 6 position multi port valve. Just replaced the diverter with gasket and the spring on the diverter stem. Reason for replacement was water was leaking out the backwash value about as fast as it was going in the return. After replacement of these part problem remains. If I select backwash nothing comes out the backwash port. If I select filter water comes out backwash and return. If I select rinse water comes out only the return to the pool. Did I put something in backward have something else damaged?

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