Finding a tiny hole in a tile pool?

Mar 27, 2017
[FONT=&quot]Hello experts[/FONT]

[FONT=&quot]I live in Denmark and took over a house with a pool 10 years ago. Unlike most pools here (Liner vinyl) it is a tile pool.[/FONT]
[FONT=&quot]It is from the 70s but has proven solid up until two month ago when it started to loose water - about 1 inch per day.[/FONT]

[FONT=&quot]I have closed all the valves for the pipes. The water level has sunk below the pool inlet valves. I also have a bottom drain but i am worried that the hole is in the concrete itself.[/FONT]

[FONT=&quot]At first i figured the hole must be at the level where the water stopped but I understand now that the hole can be at pinhead size below that level because of the high pressure. To verify I filled the pool and the level dropped again but not to the exact same level as before. If it had stopped at the exact same level I would assume that the hole would be at that level but now I am afraid the case is that leaking stopped because the pressure no longer is high enough.[/FONT]

[FONT=&quot]What do you guys think? Am I making the right conclusions here?[/FONT]

[FONT=&quot]And what is the next step?[/FONT]

[FONT=&quot]I have discussed the problem with a friend and we are planning to drain the pool completely and "jump in" to do a close up inspection of each square inch of the pool and knock on each tile to reveal loose tiles or concrete.[/FONT]

[FONT=&quot]I don't suppose some miracle treatment or sealent exist that I can just apply to the hole surface or concrete joints to seal the hole?[/FONT]

[FONT=&quot]What do I do if I can't find the hole?[/FONT]

[FONT=&quot]Any ideas are very welcome...[/FONT]

[FONT=&quot]Picture of pool:[/FONT]


Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
Houston, Texas
Hi, welcome to TFP! I would try plugging the main drain first and see if that helps. It may be easier to spot a leak in the tile while the pool is filled. Check first for cracks and missing grout. Get some leak detection dye or food coloring and squirt a few drops in any suspicious areas to see if it gets sucked into the leak. You can also use this to check the main drain before you plug it.


TFP Expert
Apr 19, 2013
Sacramento, CA
Differences in pressure generally don't affect pool leaks. If the is a tiny crack water will still seep through. Do you have a high water table? It will stop at the level of the water table which may change from day to day.

I would try plunging the main drain as zea suggests. On that note I would refill the pool. Plug the main drain and then slowly move around the pool at the level where it stopped draining with the dye. Very tedious I know.