I have an inground pool, about 20,000 gallons, and 30-plus years old. I've owned it for five with no issues to date. When I uncovered it to prep it for use this spring I found that it had drained about a foot down. I cannot find the source of the leak. Hoping for your help, and here's what I've tried so far:

Observe: without the pump running it definitely loses water, and given several days it always stops roughly 3-4 inches below the tile that surrounds the skimmer door. It seems to leak very little if at all with the pump running. There is no moisture near the filter pump or any above ground pipes. The automatic pool cover will short out when the pool leaks, further leading me to believe there is a leak underground somewhere. After a couple days of of the pool sitting at its lowest waterpoint the pool cover works fine.

From what I've read this makes it likely to be a suction side leak, but the fact that it leaks so far below the skimmer and that if left untouched the skimmer holds some water with the pump off makes me think that's not the case.

Tests: I have done the dye test on all return valves any small cracks around the skimmer and the vacuum port. I've also used epoxy to fill in any tiny cracks I found. No leaks identified and at least the same amount as it did prior to the epoxy fixes. No obvious cracks on the stairs or at the line where the water stops.

Leak detection companies are all quoting $350 to $750 without a guarantee to try to find the leak. Anything else I can try to find it myself? Thanks in advance for your thoughts.

to be thorough, I have plugged all of the return valves and the vacuum port, and then removing them one by one after refilling about an inch. No matter which one I removed the pool leaks at the same rate, further convincing me it's not a part of the return piping. But, I'm not running the pump at all because the water's so low, and not raising the water level high enough to be entering suction side through the skimmer, so that would tell me it's not a suction side leak.

  • Check the wall surfaces at the water level - where the level stabilises must be the bottom of the leak.
    – Solar Mike
    Jun 19 '20 at 4:06
  • 2
    All the pipes are connected at the pump/filter, so your conclusion in the last sentence is false.
    – Mattman944
    Jun 19 '20 at 9:18
  • 1
    Are ANY pipe ports below waterline when it stops? I would agree with the assessment that all the pipes are connected at the pump, and with the pump not running, water from any pipe will make it to every other pipe - while not leaking when running the pump puts the leak in the suction side.
    – Ecnerwal
    Jun 19 '20 at 11:22
  • Is the skimmer bucket plastic lined? , many pools used plastic lined buckets at the skimmer and bottom drains these crack even though they may be bedded in a lightweight concrete/ zonalite mix common back then but the plastic cracks as it is not as solid as the rest of the pool.
    – Ed Beal
    Jun 19 '20 at 22:49
  • Ok, thank you on the thought around water flowing through all pipes suction side. That helps a lot.
    – PoolWoes
    Jun 19 '20 at 23:02

If you can carefully dig some test wells around the pool you may find one place wetter, hope you dont find any pipes or wires though. Your troubleshooting logic is sound.

  • I wish I could, 3 ft of concrete all around surrounded by a concrete wall on two sides, one of which is where the pool cover equipment is. So, most logical place to dig (near cover equipment and electrical lines) all buried under concrete.
    – PoolWoes
    Jun 19 '20 at 23:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.