Water Behind my liner.

Jun 29, 2010
Hi All,
This is my first post so be gentle :p

I'm in my 4th summer with an in-ground vinyl lined pool. Since new, I've had to pump water out from behind the liner. The pool installer worked on this for the first year with repeated attempts at repair around the stairs. The following year I had a local and highly recommended leak detection company do a leak search which lead to another repair (patch) at the stairs. BTW, the pool installer is no longer in business.
To remedy the situation, i've constructed a piece of PVC pipe that I insert where most of the water collects and pump it out with my vacuum hose into the skimmer. I've tested the water behind the liner for salt as one pool repair/service company though it may be ground water, which it isn't.
So i guess what my question is, is there a product or technique I should try to remedy this? Everyone who's been involved in this has finally suggested that I replace the liner.
I would like to make sure I've investigated every avenue before dropping the $5k to replace the liner.

Oh one more thing.. what a fantastic forum/website!!!



TFP Expert
In The Industry
Jun 12, 2009
Exeter, PA
Do a bucket test to figure out how much you are losing. If you are losing water the next step is to find the area of the leak
Jun 29, 2010
JohnT said:
Welcome to TFP.

Do you have an idea of how fast the water is leaking out of the pool?
HI JohnT, Thanks for the quick reply.
The interesting thing is that the water does not leak from beyond the pool walls and floor (the pool installer did an exceptional job there). Therefore the bucket test doesn't work. Also, after 48 hours, the amount of water accumulating behind the liner slows down considerably which is most likely caused by the pressure equalizing.
My pool is a humped-back kidney style, and all the water accumulates on the side of the middle hump. If I leave it for at least 2-3 days, it takes about 15minutes to pump it out, regardless of how much longer I leave it which tells me the leak slows down considerably once it reaches a certain point.


TFP Expert
LifeTime Supporter
Mar 29, 2007
Coastalish 'down easter'
Welcome to TFP!!

Before investing in a new liner, I'd check every square inch of the liner in the area that has the water puddle under it, dye testing any suspect area!

That was my first thought however, upon further thinking, your pool water CAN NOT! float the liner!!! {perhaps it could IF you have clay soil or a concrete floor - but I still doubt it} (if anyone has trouble with this concept, grab a chilled bottle of Rose and take a long walk on the beach at sunset :) )

The water must be from the ground, either surface or ground water.

The water in the pool seeks it's own level, whichever side of the liner it's on! There must be more hydrostatic pressure from under/ around the pool than the water in the pool can displace to cause the bubble!

Are you loosing water in the pool?

This is interesting, and I think we're all missing the piece that will complete this puzzle :?
Jun 29, 2010
Hi Ted et al:
Yes I agree this is a bit of a puzzle. Here are some details that may help:
  • The pool has a concrete floor and the steel walls were sealed with silicon[/*:m:3pozc9fj]
  • The water that I pump out from behind the liner has the same salinity as the pool (It must be pool water)[/*:m:3pozc9fj]
  • My entire property is sand, even the footings on my house and underside of the pool therefore the drainage is excellent.[/*:m:3pozc9fj]
  • The leak rate or bubble size doesn't seem to change when we get a lot of rain.[/*:m:3pozc9fj]
  • I've had the best leak detect guy look at this 3 times. He put in a small patch by the stairs and leak-checked every other point of entrance (returns, lights, skimmer, returns, etc) and found nothing else.[/*:m:3pozc9fj]
  • The water always collects in the same area which is always on the back (hump) side and always at the point where the wall and floor meet.[/*:m:3pozc9fj]
Oh, I don't like rose.. chilled or otherwise. Could this be my problem?? :lol: :lol:

Thanks again!


New member
Aug 8, 2010
I am having the same problem since my liner was replaced and just found out (diving) that the hydrostatic valve pipe had a plug on... I bet it should not?

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