Massive Pool Leak

Question

For the last two years (since we have been in this house) the pool has leaked - at about twice the standard evaporation rate.

Three different pool leak detection companies have been here since.

One said it was the skimmer. He re-did all the concrete around the skimmer...but $1,000 later - no difference in the leak. Another company came out, just could not figure it out. Another one sealed some cracks after doing the ink test but said there was nothing major found...

Now, just last week, it went down two feet in 2 days (24 inches).

I stopped filling it and the pump has been off. It's continuing to leak. It's been 12 days, the pool is now only 1/3 full! (The stairs are no longer under water and the deep end looks less than 4 feet full).

• What could cause such a drastic leak, in such a short amount of time - out of nowhere?
• Do I have time to fix it, or is it something that needs to be figured out right away, since the pool does not have water in it?
• I don't see any major cracks. Does this point to something with the plumbing vs. the pool itself?

This is an in ground, small to medium size pool in the back yard.

EDIT

• Currently, the water is now only ~3 feet at deep end. ~60% of pool empty.
• Adding pictures soon.
• Does the drain at the very bottom, meet up with the same line as the skimmer at the top of the pool?

.
.
.
Pool contractor came out and gave us this estimate, does this seem right?

Thanks.

Answer 1

A drop of 24 inches in the water level is a definite indication that your plumbing or the pool shell is compromised.

First step is to notice if the water level continues to drop while the pump is off. If it does continue to drop the leak is most likely in the pool shell or the suction side of the pump. If it is on the suction line you should see evidence of this at the pre-filter near the pump. It will be pulling air and water rather than water. Your filter tank when you open the bleeder valve will exhaust air for a long time.

If the water level has stopped and is holding steady you should concentrate your inspection for openings in the plaster shell at this height.

If the leak is on the pressure side of the pump or the return line (which it seems a higher percentage occur) there should be evidence of its location: A sink hole or saturated ground soil. A large amount of your pool pipes are only 10-14 inches below the concrete deck. The only pipes deeper are the drains at the bottom. If the return line is suspect you should be noticing a severe decrease in pressure at the return ports in the pool.

I believe your pool shell isn't the cause of such a serious leak. If it was I would think the opening would be obvious. A drastic loss of water is most likely a cracked or split PVC pipe. Locating it is very difficult for a home owner, but seeing how the professionals failed it maybe time to consider other options: have any of the leak contractors used audio sensing devices? With this type of leak locator they will use a sensitive microphone and listen for the sound of water leaking under high pressure. The work usually entails plugging select pool ports and/or putting suspect pipe sections under air pressure.

Look for secondary signs/evidence of were the leak is originating from. Is the concrete deck developing cracks or are control joints widening? Cracks on the deck may mean pressurized water is eroding the earth the deck is supported on. Is there an area of vegetation that seems to be more lush and growing faster than surrounding plants?

If you are residing in a climate that is prone to heavy rains and high water tables keeping the pool shell weighted down is necessary. If not it would be wise not to saturate the immediate area on the outside of the shell with any more water (especially if you live on the SW coast of N.A.

Answer 2

I built in-ground pools in Hawaii and Puerto Rico for years. If your pool is plaster and not tiled you may have a "seep" issue. That is to say that the plaster has been damaged by uv and or some other environmental problem that is allowing the water to drain out like a hard sponge. If you have tile then the grout may be giving way. This usually occurs near the water line tile,or near the stairs, skimmer, and or drain. if you can post a few decent pictures of the pool I may be able to help.

Another likely possibility is that the return system is cracked (the pvc that connects the pools skimmer and drains to the pump). What year is the pool and is it fiberglass?

Answer 3

I had this EXACT same problem with my 30,000 gallon gunnite pool. Know what the problem was? A 1/4" pebble.

There is likely a hydrostatic pressure relief valve built into the bottom drain assembly (under the cover). Over a period of a week we got a LOT of rain, thus raising the hydrostatic pressure high enough around the pool to open the spring-loaded valve. That's fine, as that is precisely what it is supposed to do.

The problem was that while it was open, there was enough pressure to force a small 1/4" rock up into the valve... so it couldn't close. You will be friggin' amazed at how fast a pool can drain when that 1.5" pipe is left open 1/4". I lost about a foot of water a day... and was doing the exact same thing you are now. Spent a lot of brain cells and phone calls trying to theoretically troubleshoot the cause. Some of those theoretical reasons were incredibly complex.... at least they were when pitted against what ultimately was the real cause - a tiny pebble that got itself wedged in about the last place anyone expected to find one.