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Thread: Huge leak, several "experts" have all been stumped. HELP!!!

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    Huge leak, several "experts" have all been stumped. HELP!!!

    Ok this is my first time here and I really hope someone can help. I'll provide a ton of background info first. I bought a house last year with a large in-ground pool. The pool is basically a rectangle about 14' wide and 36' long. It is about 3.5' deep in the shallow end and 9.5' in the deep end. The pool had been empty for nearly 2 years before I bought it and the previous owner didn't speak English and was no help. It had a large crack that ran almost the entire length of the pool and up the deep end side wall. I was to told to leak test it before doing any work and has American Leak Detectors come out. They said since the pool was empty they could only check the plumbing which they charged me $650 to do. They said it good. I had a mason cut a V trench in the crack and then fill it in. After that the pool was repainted and I thought I was ready to go.

    My pool leaks after each filling always to the same point, the lower edge of the return lines and about 7" below the skimmer. I had American Leak Detection come out again and the guy dye tested some of the return lines and the area around the light, charged me $500 and again said everything was fine. He couldn't finish the job because he said the water was too cloudy as my return lines were spouting DE into the pool.

    My main problem is this... if the pool shell itself was leaking wouldn't the water continue to drop? At it's longest it went at least 3-4 months without any change, staying right at the lower level of the return lines. I again filled it and within 5 days it dropped nearly 8 inches. I have an attached spa and it drops at the same rate to the same level.

    I have now ripped up all the coping and concrete in the backyard and have most of the piping exposed, no wet dirt. The construction guy said my skimmer was leaking but I think it is just A leak and not THE leak seeing as the water level is now 7" below the skimmer.

    If anyone has ideas or suggestions I would REALLY APPRECIATE it. Let me know if more info is needed and thanks for your help.

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    JasonLion's Avatar
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Welcome to TFP!

    If the pool drains down to a specific level, then there is a leak at that level. If that level matches up with the returns, then the return fittings are the first place to look, but not the only place to look. The leak could be anywhere around the wall of the pool at that level, or inside the return plumbing. The leak can not be deeper than that, so all of the pool shell below that level is fine. But there could be a leak at the crack right at that level (and possibly above that level as well). It's a bit of a large coincidence if the leak isn't associated with the returns in some way, but it is still possible.

    Beyond that it is difficult to say anything specific. It sounds like you have been doing all the obvious things you should be doing, and some of the less obvious ones as well. Pinning down a leak location can be tricky, and requires persistence. I suggest doing a very careful inspection of the pool surface all the way around the pool at the level the water drains down to and see if you spot anything.
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Welcome to the forum. If the water line stops lowering at always the same point, that's where the leak is.

    Simply put, if the leak was lower, your pool would continue to leak, If the leak was higher, it would stop before it got to it's current stable level.

    Let the water reach that stable level and then do some detective work.
    Dave S.
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Thanks for the quick replies. There are no visible cracks at the new water line. Also if so much water is draining so fast wouldn't I see some bubbles or something near where the crack would be?

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    Re: Huge leak, several "experts" have all been stumped. HELP

    Also if so much water is draining so fast wouldn't I see some bubbles or something near where the crack would be?
    Nope. That much water can leak through the smallest, insignificant looking holes.

    If you are totally convinced the leak is not in the shell (body) of the pool, and there is not a penetration of the shell at that point, then you could have (far less likely) a broken pipe at that same level underground.
    Dave S.
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    Mod Squad JohnT's Avatar
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Plug your returns and see if it keeps leaking. Easy and cheap test. If the pool stops leaking when the returns are plugged, you have a leak somewhere in your plumbing. If it keeps leaking you are probably losing water around the return pipes and you need to seal the area where they come through the shell.
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    Re: Huge leak, several "experts" have all been stumped. HELP

    You don't say if it leaks down while the pump is off or when the pump is on. If it only leaks when the pump is on, you may have a small pin hole lead on the return plumbing that only leaks while under pressure. If so when your leak detector guy used dye detect the flow going into the return fitting with the pump off he would not have seen anything. If on the other hand it only leaks down when your pump is turned off, but not when it is on then the leak is likely in the suction side plumbing.
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    Re: Huge leak, several "experts" have all been stumped. HELP

    If you have a light dig up the light and find the conduit and check it. The main drain if your pool is so equipped could also be the culprit. Water will equalize with water around the shell. That doesn't mean that the leak is at the water level. If there is a drain tile around the pool that will allow the pool to leak to that level. Leaks if they are in the shell are pretty tough to find. From past experience a large crack like you described is almost impossible to seal without an epoxy binder. Look at www.ecosmartepoxysystems.com .
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Thank you all for the continued feedback. The water leaks regardless of whether or not the pump is running. There is no tile in the pool near drains and the water is now about 4" below the tile line. I'm wondering if there could be a leak in the main drain? My biggest difficulty with this is that if this water leaks out the bottom of the pool why would it stop at a certain point and hold? Unless it reached an equilibrium with pressure from outside the pool. However once that equilibrium was reached and I put more water in it shouldn't re-leak down to the same point, which it has done again.

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    Re: Huge leak, several "experts" have all been stumped. HELP

    You said the leak detection company did a pressure test on all of the lines, including the drain? Did they pressurize the lines and let it sit over night, a day, maybe two days? If they just pressurized the lines and it held for maybe an hour, I don't see that as a very good test.
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    Re: Huge leak, several "experts" have all been stumped. HELP

    I'm they only tested for an hour at the very most. I don't know if they tested the main drain. The first time they tested the pool was empty, the second time it was too cloudy to be very thorough in the water and I know they didn't dive to the bottom.

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    Re: Huge leak, several "experts" have all been stumped. HELP

    Quote Originally Posted by Martin Pennell
    ........I'm wondering if there could be a leak in the main drain? My biggest difficulty with this is that if this water leaks out the bottom of the pool why would it stop at a certain point and hold? Unless it reached an equilibrium with pressure from outside the pool. However once that equilibrium was reached and I put more water in it shouldn't re-leak down to the same point, which it has done again.
    I may be misunderstanding your confusion, but if a leak is in the main drain piping extending from the main drain, then it's perfectly understandable why added water would leak down to the same point. I think you're assuming only leaks between the main drain housing and the pool structure. However a leak in the main drain piping will cause the pool level to lower to the same point every time.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Huge leak, several "experts" have all been stumped. HELP

    Quote Originally Posted by gtemkin
    Quote Originally Posted by Martin Pennell
    ........I'm wondering if there could be a leak in the main drain? My biggest difficulty with this is that if this water leaks out the bottom of the pool why would it stop at a certain point and hold? Unless it reached an equilibrium with pressure from outside the pool. However once that equilibrium was reached and I put more water in it shouldn't re-leak down to the same point, which it has done again.
    I may be misunderstanding your confusion, but if a leak is in the main drain piping extending from the main drain, then it's perfectly understandable why added water would leak down to the same point. I think you're assuming only leaks between the main drain housing and the pool structure. However a leak in the main drain piping will cause the pool level to lower to the same point every time.

    How does one check for leaks in the main drain? And if they are leaking how do you get under the pool to fix it? My pool drain is down nearly 10'.

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    gtemkin's Avatar
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Quote Originally Posted by Martin Pennell
    How does one check for leaks in the main drain? And if they are leaking how do you get under the pool to fix it? My pool drain is down nearly 10'.
    I think a likely cause if it's associated with your main drain, is NOT the main drain that is 10' down; instead it's the main drain PIPE as it leads up towards your pump. Such a leak would likely be along the side of your pool or anywhere between the the side of your pool and the pump, anywhere it is at 7" below your skimmer. As PS0203 suggested, FULLY pressure testing that line would give the answer.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Huge leak, several "experts" have all been stumped. HELP

    Quote Originally Posted by JasonLion
    If the pool drains down to a specific level, then there is a leak at that level.
    Does a high water table create a possible exception to this rule? Let's say the leak is somewhere near the bottom of the pool, but there's a high water table (just a few feet below grade). Once the water level inside the pool drains down the same level as the water table outside the pool, wouldn't the equalization in hydrostatic pressure cause the leak to basically stop at that point?

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    Re: Huge leak, several "experts" have all been stumped. HELP

    Quote Originally Posted by mcaswell
    Quote Originally Posted by JasonLion
    If the pool drains down to a specific level, then there is a leak at that level.
    Does a high water table create a possible exception to this rule? Let's say the leak is somewhere near the bottom of the pool, but there's a high water table (just a few feet below grade). Once the water level inside the pool drains down the same level as the water table outside the pool, wouldn't the equalization in hydrostatic pressure cause the leak to basically stop at that point?

    --Michael
    Yes, I think that could be the case and I'm guessing the test for that would be to lower the pool a few inches below where the leak level is and see if the pool fills itself back up without rain.

    However, I think that's the less likely, more complex, scenario and the simpler, more common causes should be examined and eliminated first.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Huge leak, several "experts" have all been stumped. HELP

    Get a scuba diver to dive down and plug the main drain.
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Ok, I really hope my problem is solved now. I had American Leak Detection come out again today. They checked the plumbing again and said it was good. They then dye tested near one of the spa jets and found a screw missing on the faceplate. It took the dye. He put in a new screw and the dye stopped. He assured me that this was my problem and that the spa was drawing water from the pool in the common return line. The jet happened to be about the same level of the return lines which is where my leak always stopped. Does this make sense? Does his assessment hold water? (pun intended) Thanks again for your responses.

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    Mod Squad Bama Rambler's Avatar
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    Re: Huge leak, several "experts" have all been stumped. HELP

    Since the level happened to be where the leak stopped his assessment sounds right. A small hole can leak a lot of water running 24 hours a day.
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