Water draining from pool, possible leak?

May 31, 2015
7
Dallas Tx
Our water level around pool is dropping pretty quickly and we are trying to pinpoint the problem. We live in TX so we cant find water anywhere because of all the rain. Ground is soaked anyway. So the water is dropping with the pump off. I turned the skimmer pipe off and it continues to drain. That leaves the main drain, correct? When the main drain is closed, the water stops draining. Now what do I do? I'm assuming this means there is a leak. Should I call a professional or are there ways to try to fix the problem myself? Any advice would be greatly appreciated!! Obviously I know nothing about pools!
 
It would help us if you would add the following information to your signature



  • The size of your pool in gallons
  • If your pool is an AG (above ground) or IG (in ground)
  • If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass
  • The type filter you have (sand, DE, cartridge)
  • If you know, tell us the make and model of your pump and filter.
  • List any other equipment you have: SWG, second pump, etc.
  • Please mention if you fill the pool from a well or are currently on water restrictions

Information in your signature will show up each time you post. Signatures need to fit on five lines. It is fine to put several bits of information on the same line.

Obviously recomendations will be differetn for an above ground vinyl pool than an in-ground gunite pool.
 
i recommend you start simple. There are a few ways to troubleshoot a leak that doesn't involve much work.

The first test is to eliminate the possibility that the leak is all in your head. Try putting a bucket on one of your steps and put a brick in the bottom. Fill the bucket to the same level in the bucket as your pool water level. Leave it for a day and see if either level is different. If they are the same then it is just evaporation. You can lose up to a 1/4" a day from that alone. If the pool water level is lower than it's safe to say you have a leak.

Second you should move on to the skimmers. you will have to leave the pump off for this part. Use winterizing plugs (usually #10-12) to plug the skimmers. Monitor the pool to see if you still lose water, if yes then move on to the returns. If after plugging the returns you still lose water, then you quite possibly have a leak in the main drain. At this point you should make very sure you are prepared to move on to bigger steps like dye or air testing the line.
 
I did the bucket test and actually didn't need the bucket at all because you can visually see the drop in water level. We have now lost 8 inches of water in a matter of 24 hours. The water level is below the skimmer. The water level continued to drop even after passing below skimmer level. I have tried dye around the lights and no dye was sucked in. The only way I was able to prevent the loss of water was to turn the main drain lever. I'm assuming that closes it and prevent water from getting into the main drain pipe? Is the air testing something one can do or is that something I should call a professional to do? Thanks for your response!! Trying to figure out the steps to follow to pinpoint and fix the problem.
 
Just to clarify... you close the valve to the drain and the leak stops?

Water seeks its own level. Is the equipment pad below the pool somehow? Because what you're describing sounds like you have a bad multiport valve and the pool is draining out the waste pipe.
 
Yes, closing the valve to the drain does stop the water from draining. The equipment is set up at a lower ground level than the pool if that is what you are asking. I'd say it is maybe 8 feet below the top of the pool. The pool is actually on a hill with the equipment further down towards the bottom of the hill. How would I check to see if it is a bad multi port valve? Is that something I can even do? Thank you for responding!!!
 
Yes, closing the valve to the drain does stop the water from draining. The equipment is set up at a lower ground level than the pool if that is what you are asking. I'd say it is maybe 8 feet below the top of the pool. The pool is actually on a hill with the equipment further down towards the bottom of the hill. How would I check to see if it is a bad multi port valve? Is that something I can even do? Thank you for responding!!!
Where does your backwash drain to. Look at that pipe and see if water is coming out of it when you have the lever open for the main drain.
 
Yes, closing the valve to the drain does stop the water from draining. The equipment is set up at a lower ground level than the pool if that is what you are asking. I'd say it is maybe 8 feet below the top of the pool. The pool is actually on a hill with the equipment further down towards the bottom of the hill. How would I check to see if it is a bad multi port valve? Is that something I can even do? Thank you for responding!!!
There should be a total of five pipes going to the multiport or backwash valve. In, out, to filter, from filter, and waste. Waste might go to a hose or into a storm drain or the sewer. WIth the valve set to filter -normal- and the main drain open, you shouldn't see any water coming out the waste pipe. If you do, mystery solved. I'd bet money on it. It's a fairly simple repair.
 

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Where exactly is this main drain lever? Is it connected directly to a valve immediately below the main drain in the pool, or is the valve somwhere in the pipe from the main drain to the pump?
 
We've had the drain open for about an hour now. No water coming out. The water level in the pool has dropped about 1/4 inch. Any suggestions on what to check next?
Wherever the leak is, it has to be below the water level in the pool and after the main drain shutoff valve. Don't forget that the water could be making a U, coming down the main drain, through the pump and filter and back up to some other pipe. That's the best I can do without being there in person.
 
Good thinking on checking the backwash. A quick way to tell is to take off the sight glass and turn the pump on, it will show itself immediatley if it is leaking.

I think if your visible plumbing and equipment is ok then you may want to hire a pro to pressure test the returns and possibly the main drain. Typically a main drain job will require you to drain the pool or like i mentioned before, find a service company with a diver.
 
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