Pool Leak. Process of Elimination

[bigku22]

Hello All. I have a pool leak and need some guidance on troubleshooting the location.

First my pool info: 16x32 gunite inground pool. One skimmer, one main drain. I realized I had a leak end of last year (having to add water daily) which the pool guy identified as the skimmer pipe. This spring we replaced the skimmer, and resurfaced the pool.

Upon opening, I was running the pump 24/7 (new plaster), and for a week it did not appear the pool was leaking and I did not need to add any water. Thought everything was great. Unfortunately, after transitioning to only running the pump 8-12 hours, I noticed the leak had returned as I was losing water (inch or so per day).

This tells me (based a lot of what I've learned here), since the pool I believe is leaking primarily with the equipment off that I likely have a suction side leak. I let the water get below the skimmer, but there is still water in my skimmer bucket (is this normal if I have a skimmer leak?). Other possibilities I guess are main drain or pool light leak, but the water did not drain out over the winter (I believe eliminates the main drain possibility).

Pool guy is coming back tomorrow, he has a theory since we replaced the skimmer/pipe early in April and it got cold right after (weird weather here in Michigan as always) the hydraulic cement might have not set properly or we had a small crack. I just wanted to try and be prepared with as much knowledge as possible.

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[AftonJeeper]

So if you leave the pump off it drains down to the skimmer, not below?

If there is water in the skimmer I would think there is no leak below the level of the water.

Is there any air in the pump basket when running?

 

[bigku22]

It has dropped below the skimmer and it still losing water (approx. 1/2inch to 3/4 inch per day).

Yes, the skimmer basket still has water.

With the main drain and the skimmer fully open there was, but if I modified the flow the lessen the skimmer the bubbles would disappear.

When the equipment was on I was barely losing anything or it was not very noticeable. I have a slab of concrete which has dropped below the others right next to the skimmer. The fact I am still losing water below the skimmer would lead me to believe either the main drain or the skimmer pipe below have to be the source?

 

[AftonJeeper]

I have a slab of concrete which has dropped below the others right next to the skimmer. The fact I am still losing water below the skimmer would lead me to believe either the main drain or the skimmer pipe below have to be the source?

I think you are on to something here. I'd adjust your valves to remove the bubbles and keep it running until you are ready to repair it.

Ripping out concrete is no fun.

 

[bigku22]

Pool guy came by. We are going to test and isolate the main drain and then the skimmer to try and be sure. Running just off the main drain right now, skimmer shut off, no bubbles in the basket I will check the water level tomorrow after 24 hours.

Yea, unfortunately this seems to be trending to rip out a concrete slab and replace the suction side piping. Will update with results of the testing tomorrow.

 

[bigku22]

Update. We ran the main drain isolated for 24 hours. No leak, didn't lose anything and no bubbles in the pump basket.

Will isolate the skimmer line and try that next.

Pool guy is thinking that it is in the return lines. Is this possible that the returns could be leaking with the equipment off, as in water pushing back into the lines and leaking out at some point? I can let the water leak to see if it goes below the return lines and stopped, but wanted to see if that was a plausible theory?

I'll update progress tomorrow.

 

[bigku22]

Update. We shut the pump off last night with the skimmer line closed, and NO LEAK. Haven't lost any water in 24 hours even with the equipment off. We are going to fill and run just off the skimmer to be sure, but I think we have isolated the leak. That's the good news.

The bad news, it's very likely a slab of my concrete deck will need to be broken up to reach the leak. Pool guy is coming out this weekend to pressure test to see if we can pinpoint exact location and minimize the damage. Will update once we verify it is the skimmer line with the testing, and fixing it options/cost.

 

[AquaBoy]

Thank you for these updates. I had a leak that I thought I had pinpointed to being a pipe under the concrete, but thankfully it turned out to be a simple fix of replacing the sand filter top assembly. My pipe is about 10 feet in length between the pump and the pool, so rather than calling American Leak Detection and forking out $350 I was prepared to just cut the concrete myself, fix the pipe and install a grate so that in the future I could easily get to it if it happened again. Previous owner loved him some concrete. Half of our entire back yard is concrete.

Hope you have the cheapest results possible since I definitely know what you're going through right now. The one silver lining that I came to realize was that while the expense can be a tough bullet to bite, over time at least you won't be losing money on chemicals just leaving the pool. I had just resigned myself over the course of the last six months to running a steady stream of hose water into the pool whenever the filter needed to be run (mine leaked only when pump was running) and was losing money on water bills and chemical loss. Keep us updated, it always helps when someone has a similar problem in the future and has something to refer to when troubleshooting!

 

[bigku22]

No problem. The fantastic info on this sight has helped me in a number of ways, so more than happy to contribute.

Update, we confirmed it's the skimmer line. I filled the pool back above the skimmer, closed the main drain to run just off the skimmer, and couldn't even get enough flow for the pump to properly prime.

For now, I will be plugging the skimmer and running just off the main drain to prevent any further water loss.

Pool guy is coming by after the holiday to pinpoint the location and tackle the repair. Unfortunately I don't have one sliver of grass in my entire backyard, all the piping is under concrete. Glass half full the distance between the suction lines and the equipment pad is only about 10 ft (2 slabs). I'll take some pics and provide the cost info. If we can pinpoint the location we can saw cut a portion of the concrete out and just replace that location, but we will have to see.

Relieved it appears we have definitely found the leak location, and we can operate the pool in the mean time without losing more water until the repair. But the repair isn't going to be fun.

 

[AquaBoy]

Definitely agree about the repair not being too enjoyable, but that is definitely some silver lining for sure. If for some reason the pool guy cannot pinpoint the exact location, I'd recommend what I was going to do and just cut around that pipe and throw a grate on there so that in the future you don't have to do it all over again should something happen. I do have some grass, but unfortunately all the pool lines are on the side of the pool where the entire concrete section is. Closest grass is probably 30' away. Liked it at first because it kept more debris from getting into the pool, but when a line breaks (and I'm sure it will since we live on an island and our "soil" might as well be sand, meaning constant shifting), I'm going to pay for that convenience!

 

[bigku22]

Sorry for the delay, after our pool guy finally finished all his openings for the season he finally came by this week. As predicted the leak was found where we had a slab dipping. Back history, I've only owned the home for 2 years, the pool was installed sometime in the 1970s, and it appears the current leak was previously fixed at some point, and had issues again. Not knowing exactly how the pool was plumbed (and what type of piping is under there) makes it more of a challenge to determine the leak. A positive, it appears all my underground pluming was replaced at some point, since none of it is copper and I am positive the pool was originally built was copper piping (there was a very old sand filter and copper piping on the equipment pad when we bought the house).

But, the best news, the leak is fixed, pool is working perfectly again. Total charge for the fix was $650. I will post the pics in the next post.

 

[bigku22]