Mystery Leak! Please help save my pool!

Sparks98

New member
Jan 6, 2020
3
Austin, TX
I have been on a multiyear hunt to find this mysterious leak in my pool! The particular mystery has been that for a couple of years, the pool would only leak in the summer. Now, however, having ignored the issue for too long, the pool is leaking more than ever, and in the winter too. It's currently at 1.5 inches per day.

Please help confirm my assumptions: For a long time, I suspected the return lines, pool lights, etc, until the water level dropped below all of that and the pool kept leaking. That left only two other potential options: 1) A very long (15 ft) hairline crack that runs along the bottom of the pool, or 2) the main drain. The main drain has been shut off for years (another story), and my pool guy said that the hairline crack was probably just in the top layer of plaster and that the main drain was the likely culprit. The rest of the pool is crack free, including around the stairs.

So I plugged the main drain. I plugged it hard and good. I put in a plug, then covered the whole thing in hydraulic cement, then covered that with a water-tight red guard membrane.

But it did not stop the leak. SO, with no other culprits, do I have to assume that water is escaping through the hairline crack? If so, that doesn't bode well for the structural integrity of my pool, does it? Do I need to do the full scale repair, ie, cut out the plaster around crack, add mortared rebar staples, and patch?

I am attaching photos.

I'm not sure when the pool was built, but probably in the 80's. The pool decking around the pool is wonky, cracked, and angled, so it's clear there's been some movement in my central Texan soil.

Here's the pool, showing that the water level is below all of the lines.
IMG-1053.jpg
Below is what the crack looks like for most of its distance. IMG-1057.jpg
Below is the worst part of the crack.IMG-1056.jpg

Thank you so so much for any help! I try and do all of my repairs myself, so but I may have to bite the bullet on this one and hire someone. I just wanted to make sure I am informed before dropping all of that money!

Thanks again,

Adam
 

homegameroom

Bronze Supporter
Sep 23, 2015
219
Sunrise,FL
You can try to put some food coloring in a syringe (or just use the bottle if you won't be using it for food afterwards) and squirt it (gently so you don't create a swirl of water) at the crack and see if any seeps out. You can repeat the process at the drain that you think is sealed as well to verify everything is good there.

Pool plaster does not like to be exposed - try to fix it ASAP!
 

homegameroom

Bronze Supporter
Sep 23, 2015
219
Sunrise,FL
And don't forget that pools will drain to the level of the leak or the water table. Check around the top of the water line for any other defects too, though I'd guess you're at the water table for your area.... As a result, if your current water level is not changing you may have to add more water to help identify that leak for the dye to seep out.
 

Sparks98

New member
Jan 6, 2020
3
Austin, TX
Thanks for the response!

I've done a dye test, but I couldn't spot the leak. With a 1.5" loss/day, do you expect that I should be able to see the dye being sucked out easily? I can try the test again, as the last test I did was in the summer. Maybe it's losing more now.

The pool is still draining every day, so we're not at the water table yet...
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,779
Houston, Texas
Is the crack running the length of the pool or across? Can you post a photo of the area around the pool? It may be one spot along the crack that is all the way through the shell, and it may have washed out some of the earth under the pool, making the ground more unstable. If it has drained down past all other possible exits in the pool, you have to assume the crack is the problem. You will have to leak test the entire length of the crack to find the problem area. You may want to consider a professional leak detection service.
 

Sparks98

New member
Jan 6, 2020
3
Austin, TX
Thanks for the help!

The crack runs lengthwise down the pool. It's probably about 15-20 feet long.

You can't see the crack in this photo, but you can see the decking. The worst spot on the decking the the back by the skimmer, where the decking has sunk back into the yard.

IMG-1053.jpg

I will try and leak test all up and down the crack and let you know!
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,779
Houston, Texas
I can see that it looks like the front left edge of the deck over the skimmer is higher than the right side. Are the two sides seperated by a crack in the deck or is that were two slabs of concrete butt up to each other? I'm assuming its the later since it looks like an identical division at the bottom of the picture by the steps. If the deck near the skimmer is messed up that's were I would start looking. Is your yard graded to drain on that side of the yard going toward the fence in the picture?