Mystery Leak

[jr6]

Hello,

Issue with a leak in Vegas. Bought house with 15+ year old Pebble-tec, not super well cared for and needing repair soon. Shortly after moving in, slow leak started. Not very noticeable. Eventually adding water every day, and realized we were losing 6 inches a day by the second summer in the house. Time to take action. Used to have a "pool guy" who poorly maintained chemistry and also said the water loss was normal when it was crazy hot. Hence, I'm now a member here.

But back to the leak. Definitely a problem. Let it ride for several days to see where it stopped. Leak stopped about return line height. Drained pool. Had lines tested. "No leaks" anywhere. Some cracking in spa wall with visible rust from internal rebar. Likely culprit? Nothing else obvious and needed to resurface anyway. Chipped it all out and had spa wall rebuilt to 2025 standards (it was not sturdy). Lots of spots with water damage under the plaster. Some rebar had, in fact, rusted away quite a bit. Freshly surfaced pool filled today. Still leaking. Brutal.

Any thoughts on leak detection tips and tricks? We are talking about an inch every two hours from a 13000ish gallon pool. The real bummer now is I'm trying to keep chemistry balanced while constantly adding water to not ruin the cure while figuring this out with the contractor.

 

[Bperry]

Hello,

Issue with a leak in Vegas. Bought house with 15+ year old Pebble-tec, not super well cared for and needing repair soon. Shortly after moving in, slow leak started. Not very noticeable. Eventually adding water every day, and realized we were losing 6 inches a day by the second summer in the house. Time to take action. Used to have a "pool guy" who poorly maintained chemistry and also said the water loss was normal when it was crazy hot. Hence, I'm now a member here.

But back to the leak. Definitely a problem. Let it ride for several days to see where it stopped. Leak stopped about return line height. Drained pool. Had lines tested. "No leaks" anywhere. Some cracking in spa wall with visible rust from internal rebar. Likely culprit? Nothing else obvious and needed to resurface anyway. Chipped it all out and had spa wall rebuilt to 2025 standards (it was not sturdy). Lots of spots with water damage under the plaster. Some rebar had, in fact, rusted away quite a bit. Freshly surfaced pool filled today. Still leaking. Brutal.

Any thoughts on leak detection tips and tricks? We are talking about an inch every two hours from a 13000ish gallon pool. The real bummer now is I'm trying to keep chemistry balanced while constantly adding water to not ruin the cure while figuring this out with the contractor.

Welcome! And sorry to hear it’s on these terms.

You can hire a leak detection service to come out and find it, they seem to be pretty competent and will swim the pool.

Before that, you can try to see where the water stops again and that usually points to the culprit. Any protrusions in the surface are suspects. Skimmers are especially prone, returns outlets, lights, drains, etc.

You can grab some leak detection dye from the hardware store (or food coloring) and fill a medicine dropper with some of it and squirt a few drops near any suspected item and if there’s a leak you can find the dye getting sucked into it. The trouble is that it’s hard to not disturb the water while doing this and that makes it harder to see. But is pretty cheap and can find obvious leaks.

 

[Jimrahbe]

6,

Let's assume the return lines are good, because they tested ok.

Logic says it is not a skimmer issue as that is way above the return lines.. And if it stabilized near the return lines, then a main drain leak is unlikely.

That leaves the light fixture... or maybe a vac port line...

Light fixtures are a pretty common leak point..

If this were my pool, I would remove the light and check the point where the cable leaves the fixture..

That said, a inch every two hours seems an awful lot.. Another place to check, if you have a DE or Sand filter, is your backwash line... If it goes straight to a sewer, you might not know it is leaking water..

Thanks,

Jim R.