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-   -   Inground Pool Leak - suggestions needed (http://www.diychatroom.com/f7/inground-pool-leak-suggestions-needed-98711/)

hravenkel 03-17-2011 04:56 PM

Inground Pool Leak - suggestions needed
 

I own a 33 x 14 concrete in ground / enclosed (IBG enclosure) pool that was installed in the mid to late 70s. This past fall I noticed that the pool was losing quite a bit of water such that I had to add an inch or more every day. Evaporation is rarely a problem as we keep the pool covered and it is indoors. Also there are no visible cracks or holes in the pool - either structural or cosmetic.

As the Michigan winter was fast approaching, I went ahead and winterized the pool by lowering the water level so that it was below the return lines, disconnected and drained the pump, the filter, and the heater, and blew out all of the lines. All was well until a month later when I noticed that the water level had dropped significantly (1-2 feet). I decided to wait and see where the water stopped drainign. After another week or so the water leveled off at the pool light.

I originally suspected the light as the source of the leak and promptly disconnected the light and found nothing to be amiss in that area. The copper conduit for the electric was still sealed and was, in any event, 6 inches above the level at which the water had stopped draining. Next, I drained the pool (not necessary, I know, but I plan to repaint it in spring anyway and it makes working on it much easier) and pressure tested all the suction lines with air and water (the pressure testing kit is from Anderson Mfg and works great). I did not pressure test the return lines as they were 1 ft to 2 ft above the level at which the draining stopped. The drain line did not pass a pressure test of 20 psi. Water pressure in that line decreased slowly and air pressure rapidly.

Knowing that the leak was in the drain suction line and assuming that it would be located in that line at the same level as where the water had stopped draining, I cut a 2 ft x 2 ft hole in the concrete deck and proceeded to dig (not easy!) a 4.5 ft deep hole around the suction line from the drain. I am now well below the level at which the water stopped draining.

The problem: I canít find a leak anywhere in the now-exposed section of the drain line! I double checked my pressure testing results and this line fails each time (wonít hold 20 psi of water for more than a few seconds). And I am certain that I have exposed the line well below where the water stopped draining.

Because of the tight quarters, I canít dig any deeper and my next step is to punch a hole in the bottom of the pool near the drain to gain access to the remainder of the suction line and the elbow joint. Could it be that the leak is actually below where the water stopped draining? This doesn't make any sense to me, but now Iím not sure - I can't think of any other explainiation. Iím VERY reluctant to put a hole in the bottom of my pool based on speculation. Help!

ANY and ALL suggestions are welcome! Thanks.

nap 03-17-2011 05:39 PM

try pressurizing the line and listening to the pipe in the excavation. It might help to point you to which side of your excavation the break is.

If that doesn't help, cut the line and cap it (in your excavation) and recheck. That will definitively allow you to isolate the leak to one side or the other of the newly capped line.


.
Quote:

Could it be that the leak is actually below where the water stopped draining?
yes. Depth of water equals pressure. If the lower water level causes there to be enough less pressure on the break, the leak will stop, or leak much less anyway. If you adjust your pressure as you are testing, you will likely see this in action. Once you reach a pressure that is below what the water at the ending level exerted, you will likely not be able to cause the cracked pipe to leak.

STL B. 03-18-2011 12:42 AM

If the water drains down below the shallow end floor you will not find the leak by digging down beside of the wall, the leak will be deeper than that. Your pool prolly has black polly (lawn sprinkler line) and it fails with age. I would try a couple things first...

1. plug all lines at pool wall and plug the main drain line at drain in the deep end of the pool......filler up and wait if it dosent leak it's in a pipe or at the pump/filter. If it still leaks it's the light conduit ( a fast and easy fix with great stuff foam) or a crack in the shell


2. some times pool builders install a spring loaded check valve in the main drain, it allowes ground water to pass in tp the pool if pressure builds from around the pool ( when you drain the pool it releaves pressure and keeps your pool from becoming a ship and floating ) Anyway often times sand and debris will get caught in the valve seat and cause a leak at the main. Check this first

3. as nap mentioned listen to the pipe (cheap auto stethiscope $10-$15) there's no way you would miss the noise of water rushing out of a cracked pipe.

4. call a pro some specialize in finding leaks and do it for 8hr. a day. It would cost between $250-$1000 depending on how far they go. If this is a large leak you could pay that in water over the coarse of a season.....besides that there's lots of water leaking near your foundation...not good

Lastly I doubt the main line is the culprit ( it's fairly rare around here ) but if it is just plug it and forget about it plenty of pools have pluged main drain lines and work fine. DO NOT hammer out a hole in your pool unless you want more costly trouble in the future. Look every where before you dig, I fixed a leak at a heater last year after the owner dug around the entire pool and exposed all the lines in search of a leak in the pipe........ You should have seen that guys face when I found it above ground...ha..ha He prolly dug 10-15 tons for nothin just to have to shovel it all back in.

hravenkel 03-18-2011 11:12 AM

Thanks for the help. Here are a couple of thoughts re: your suggestions.

[quote=STL B.;611742]If the water drains down below the shallow end floor you will not find the leak by digging down beside of the wall, the leak will be deeper than that. Your pool prolly has black polly (lawn sprinkler line) and it fails with age. I would try a couple things first...

The water drained to the middle of the light, which left a few feet of water in the shallow end. The drain suction line I have exposed so far is PVC, not black poly, although the drain itself looks like it may have grey poly feeding out of it - not sure what this means.

1. plug all lines at pool wall and plug the main drain line at drain in the deep end of the pool......filler up and wait if it dosent leak it's in a pipe or at the pump/filter. If it still leaks it's the light conduit ( a fast and easy fix with great stuff foam) or a crack in the shell

When it drained to the light, the pump, heater and filter were all disconnected and winterized. Also, the water stopped draining well below the skimmer and return lines. It also stopped well below the light conduit. I checked the light shell and it is in good shape. Plus, I know that the drain line is not holding pressure.

2. some times pool builders install a spring loaded check valve in the main drain, it allowes ground water to pass in tp the pool if pressure builds from around the pool ( when you drain the pool it releaves pressure and keeps your pool from becoming a ship and floating ) Anyway often times sand and debris will get caught in the valve seat and cause a leak at the main. Check this first

My pool doesn't have a check valve. We live on a hill and have extremly good drainage with no water table issues.


Lastly I doubt the main line is the culprit ( it's fairly rare around here ) but if it is just plug it and forget about it plenty of pools have pluged main drain lines and work fine.

I'm reluctant to run my entire pool just using the skimmer intake. Can this be done?

STL B. 03-19-2011 12:15 AM

Your pool will work fine using only skimmers. But you should'nt worry about that because your leak is going to be at the light niche. It is one of the most common places for leaks and is caused by not keeping your water balanced properly, acidic water has corroded thru the copper conduit at the rear of the light niche. Still an easy fix though just get your hands on some "great stuff" and give a shot or two in to the conduit at pool side. Another fix is to go to the pool store and get some "leak seal" it's a super sticky caulk like goo that doesnt dry, anyway with the light and niche dry pull the light and set it on the deck then apply leak seal to the cord and stainless niche. You want to create a bridge of sealer over the threads where the copper and stainless meet.

nap 03-19-2011 08:54 AM

Quote:

STL B.;612346] But you should'nt worry about that because your leak is going to be at the light niche. It is one of the most common places for leaks and is caused by not keeping your water balanced properly, acidic water has corroded thru the copper conduit at the rear of the light niche
. You did notice where the OP said the leak stopped 6 inches below the conduit in the light and the main drain failed a pressure test, right?

STL B. 03-19-2011 10:03 AM

Yea I saw that but the OP didnt give a time line on the events. I would guess that the OP gave it time to leak down and it evaporated to below the leak. OR the leak could be around the face ring of the niche. Or the main drain line is leaking and needs to be plugged off but it's not likely. Either way the main should be plugged and the water raised it's the only way to know for sure. About the pressure test failing there's plenty of pool guys who cant do it properly so not that I doubt the OP's skills but they may have missed something while performing the test.



Hey OP how fast is your leak?...........inches a day or feet

hravenkel 03-21-2011 08:46 AM

Pool Leak Fixed!
 
Pool leak fixed!

The light fixture was not the issue as it is embedded in 10 inches of concrete and I was excavating directly behind it and there was no sign of water infiltration.

Not wanting to run with just my skimmer, since it would make heating the pool more difficult (the drain pulls colder water from the bottom of the pool to the heater), I ended up excavating further down and exposed a coupling between black poly from the main drain and PVC piping to the pump. It ended up being something like 6 feet down and approximately 2-3 feet below where the pool stopped draining. After the joint was exposed, I ran another pressure test with water and observed a significant water leak at the joint. I removed the PVC/Poly joint entirely and cut the poly back about 4 inches. It turns out that the poly had split just past the point where the PVC was inserted and the metal clamp was attached. After inspecting the poly (and not wanting to tunnel under the pool) I replumbed the PVC/Poly coupling, reinforced it with plumberís tape and ran all new PVC to the pump to make sure there was as little torque on the new joint as possible. Once completed, the line passed 20 psi / 10 min. pressure tests with air and water. Reluctantly, I filled the excavated area, careful not to crush the new PVC/Ploy joint, and verified the integrity of the joint Ė it passed. All that is left is cleanup and pouring new concrete.

I estimate that this job took 15 hours and approximately $200.00 in tools and supplies (PVC pipe, couplings, glue, metal bracket, tape, etc.) to complete - $600.00 if you add the cost of the Anderson Mfg pressure testing kit, which is worth its weight in gold.

Thank you both for the help and suggestions! :thumbup:

nap 03-21-2011 10:14 AM

glad to hear some logic and persistence was rewarded.

Now about that pressure tester. Just how much does it weigh?

(let's see, with gold @ at 2067.51 rupee/gram...carry the 3....7 guzinto 87..:eek:)

You say it was $600 new? I'll give you $400 if you pay shipping!!!!:whistling2:


You might want to wait on pouring the new concrete and give the fill time to settle well. Then, when pouring the new concrete, use pins to attach the new concrete section to the old section to avoid separate lift or settling.

hravenkel 03-21-2011 04:50 PM

The total repairs cost me $600.00 if I added the cost of the pressure tester, which was the $400.00 kit from Anderson.

I think I will take your advice and wait to let the fill settle. Instead of just filing the hole I cut in my decking with solid concrete, I was considering pouring a separate concrete lid with beveled bottom edges and pouring a matching frame around the hole to avoid having to bust up concrete in the event I need to access that area in the future. Then again, maybe not.

Thanks again! :)

nap 03-21-2011 08:39 PM

If you do the lid, you will want to apply sealant to where it meets the rest of the concrete. If not, you might end up with dirt washing up when it rains. Just use a sealant that can be cut or removed.


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