Water stuck behind liner

[Tomwk196]

In NJ we have had substantial rain every week. Most recently 4 heavy straight days. I lowered the water level just a few inches before the most recent storm but still kept it just within the skimmer opening. I now have about 4 spots where the liner clearly has water behind it. (3 spots are fairly minor, 1 is much more noticeable). We switched from concrete to pavers 2 years ago and that is when this seemed to start happening. The company that replaced my liner 2 years ago just told me to never drain the pool before rain. Let the pool fill up and even overflow if necessary. They said when the water level in the pool is lower than the ground water, it will allow water to infiltrate behind the liner. Does this sound right? Kind of makes sense… equaling out the pressure I assume.

I’m also looking into better drainage solutions to move more water away from the pool area. I’m wanting to close my pool now but am nervous to do it while I have this issue present. May take 2-3 weeks to subside assuming no more substantial rain. Thoughts or advice?

 

[Texas Splash]

Does this sound right?

Good morning. I'm not sure about that comment. I can understand keeping the pool full so the liner doesn't try to float up from the bottom. It may also help to apply pressure against the side walls, but I would imagine there is always a chance of water slipping between the liner and wall from various areas such as a liner tear, opening from above in the decking, or perhaps seeping up & over from the waterline in an over-flowing pool if the track or deck coping isn't water tight.

Let's see if @Mdragger88 has any other thoughts though.

 

[Newdude]

Two thoughts. With the timing of the patio changes, it's either entering from the front or the back. (I KNOW ) but hear me out.


If the liner is loose in the track it may allow runoff to hook around and get behind the liner. Liner lock should wedge the connection and stop water from getting behind the liner if so. It's $25 for 120 ft on Amazon and I believe all vinyl pools should preemptively be LL'd so no spots pop out down the road.



Or option 2 is it's getting under the patio and through the gap between the liner track and wall.



You can test this (once liner locked) with a hose close to the pool. Give the coping area a 10 min soak and check to see if any water made it behind the liner. Then move back a little and repeat until you made it all the way back towards the house.

If you can't replicate it, it's likely ground water.

 

[duraleigh]

I have only skimmed this thread but the hill above the pool looks like your culprit.

Rainwater is absorbed into the side of the hill and then makes it's way own and around the pool as groundwater. That equalizes the pressure on both sides of the liner allowing your liner to float. It needs to be fixed or your liner will eventually not go back to the correct shape (wrinkles)

The fix is to get the groundwater from that hill to drain away so it will stay lower than the pool water. Are you familiar with a wellpoint?

 

[Mdragger88]

I agree with @duraleigh - the water from the hill must be dealt with. Well points are definitely important if ground water is an issue but there’s also the run off factor.
I would hate to see all that stuff on the hill end up in your pool/all over your deck. You need to divert any run off around & away from the pool & patio area.
This is a multi faceted approach along with checking the things @Newdude mentioned.