Pool leak help / advice (only leaks when cold / pump not running)

[dm123]

Hi all
I posted this same issue last year. Long story short our pool leaks, but only in the winter time when we aren't running the pump. IT leaked like this last winter, but once we started it up for the spring / summer, we had absolutely no issues with leaking or water level. We closed the pool in September. By the end of October/first of November, it had lost about 2-3 feet of water. We filled the pool back up on Nov. 10th so we could run the pump during a cold front (our pool can't be winterized because it sits below the water table, per the pool company). Fast forward to now, and it's already lost 8+ inches of water since then. What could be causing it to leak so much, and only in the winter time?

Backstory -- we did have leak detection done in late December / early January of 2018/2019. They could only find two small holes which they patched. By early February of 2019, it was down 8-12 inches+ so the patches obviously didn't work or weren't the cause of the issue. As I said, we had no problems this summer of 2019 with losing water or having to refill at all.

My question is this: since it is losing so much water, what is our best bet (or if you have any other suggestions, please let me know! I am at a loss at what to do).
1--- fill it and try to get another pool company to come out and do another leak detection?
2--- let it drain, and try to repatch the original patches that didn't work last winter?
3-- let it drain, and since it will be low enough, winterize it then and wait until spring to try to fill back up and see what's wrong (we have a safety cover, so I don't know if it would break it / make it loose).

Any help or advice is greatly appreciated. We are perplexed to how it could be leaking this much, but only in the winter months!

 

[YippeeSkippy]

This is a vinyl lined pool, right??

Maddie

 

[1Sammy]

Have them pay attention to the suction lines.

 

[dm123]

This is a vinyl lined pool, right??

Maddie

yes vinyl lined

 

[dm123]

Have them pay attention to the suction lines.

Thanks, I will ask them. So do you think wait until spring or have them come out soon?

 

[Arizonarob]

Let it drain down till it stops, wherever that point is, will be where to look for the problem(s).

 

[1Sammy]

Let it drain down till it stops, wherever that point is, will be where to look for the problem(s).

Not sure if i would take a chance on doing this unless i was 100% sure i had excellent drainage from the surrounding ground to Below the deep end of the pool.
Needs to be looked into now.

 

[dm123]

Not sure if i would take a chance on doing this unless i was 100% sure i had excellent drainage from the surrounding ground to Below the deep end of the pool.
Needs to be looked into now.

This is what I'm worried about. It's lost so much water already. I just don't see how it can be leaking ONLY in the winter and ONLY when the pump isn't on. It continued to leak after the holes were initially patched, which makes me think it's not a tear in the liner. But what else could it be? I also don't trust the pool company for answers and am too uneducated to try to think of what could be wrong on my own (besides a small tear in the liner). It's still draining, but I'm measuring it to see where it stops. I guess I will call the pool company this week and have them take a look.

 

[jmhjgh]

Do you have any leakage from your backwash line? I would make sure your valve on your sand filter is in good shape.

 

[swimcmp]

Do you have a main drain? You said you have a high water table correct? It is very possible that a main drain could leak if you have a high water table it could be pulling ground water in when the pump is running and letting pool water escape when the pump is off. I don't understand why a high water table would not permit it to be winterized. I have built several pools close by lakes (within 10 feet of water) and have never had an issue with winterizing them. We also don't drain any water from them.

 

[1Sammy]

Do you have a main drain? You said you have a high water table correct? It is very possible that a main drain could leak if you have a high water table it could be pulling ground water in when the pump is running and letting pool water escape when the pump is off. I don't understand why a high water table would not permit it to be winterized. I have built several pools close by lakes (within 10 feet of water) and have never had an issue with winterizing them. We also don't drain any water from them.

Your last sentence says it all "We also don't drain any water from them." A draining pool left over the winter in a high water table area can pop out of the ground.

 

[Ben7878]

If it only leaks when the pump is off you need to have a leak detection service run pressure tests on your plumbing line. It is most likely a leak is a suction side plumbing line, i.e. drain or skimmer. If there is a leak in skim/drain plumbing, when the pump is running these lines won't leak, when the pump is off they will.