I have an issue with my inground pool. I purchased a home about 4 years ago and after our first year (during the 2nd winter) our pool completely drained itself about a month after I put the cover on it. I was completely perplexed, but I thought maybe the liner was old and needed to be replaced anyway as the pool was about 10 years old. Also, when I filled the pool with water and informed the water company, they told me that 2 years earlier the previous owners had filled the pool for replacing the liner as well. That was just great news to me. :(

Anyway, another 2 years later and I have the same problem again. My water is draining and I don't know what to do. I kept my pump running all year (even during the winter) because if I ever turned it off the water would drain quickly... and once I turned it back on the pool filled itself back up.

A couple of items to note, when I had the liner replaced the pool guy had a hard time getting all the water out of the bottom of the pool because the water table was slightly higher than the bottom of the pool and it kept seeping in. 2nd he told me that my main drain had a relief valve so water could flow from ground into the pool.

What can I do so I don't have to go through this every year or couple of years?

Im not sure why there is a relief valve on your pool. Im thinking its an above ground pool of normal fashion. The liner is like a plastic bag. That is really all there is to it. The thing I would worry about most is the retaining structure. If there are flaws or rust that can be abrasive and caus the liner to leak. Another thing you should be able to do is a leak test using a dye. Every 2 years is very unusual for a liner replacement. Also is there sand under the liner?

The pool guy guy told me that the relief valve was to allow water to come in through the main drain of the pool when the pressure underneath the pool is greater than the pressure of the pool itself. If that valve were not there water would create bubbles underneath the liner.

The pool is indeed an inground pool and yes the pool is lined. The walls of the pool behind the liner (at least the first three feet) are made of concrete. The bottom of the pool is sand while at the main drain there is a little bit of concrete there, but it really does no good as water continues to seep up and keep the mixture wet.

When the liner was last replaced we did a through investigation looking for something that may have caused the liner to tear (i.e. piece of metal or sharp rock) but did not find anything. The pool guy told me that the relief valve will allow water in from underneath the pool, but if a small stone or debris gets caught in the valve and it can't seat itself the water will drain out of the pool in the ground when the water table drops.

So I guess my question is, what can I do to keep this from happening? Can I stop that relief valve from ever opening? Or just replace the valve all together?

HELP!