Phantom Leak Discharging Through Waste?!

[javajnkie]

Hi,

I hope you all have some ideas, because this phantom pool leak issue is driving me completely insane! I've lived here nine years and haven't had any real problems with the pool until this year.

Here's the story: The pool is a rectangular, 16'x36' vinyl-lined in-ground pool (the liner is over concrete? concrete/vermiculite mix?). It was built sometime between 1973-1975. There is no main drain at the bottom of the pool.

Since I opened it this summer, water has been pouring out onto the street from my waste/backwash pipe. To start, I replaced the multiport valve gasket. Initially, the pool was leaking down to the point of the return and intake ports, so I assumed the leak was coming from there. The return port gasket was bad, and since I had patched the liner in the corner last year, I figured that probably had something to do with it too.

So I bit the bullet and $3500 later, I have a brand spanking new liner. They installed it last week and by Thursday, I had it refilled and ready to go. I thought. Then the city knocked on my door to ask why water was pouring out to the street. By Friday night, the water had dropped down to the return and suction lines. By yesterday, it had dropped another 5 inches. Now I have about 10,000 gallons left in the pool and about 4" of water in the shallow end.

The pool guys who installed the liner came out yesterday and dye tested around the stairs and the ladders. He couldn't find anything and is completely confused (as am I) as to why it's pouring from the waste/backwash line when the pool water level is now well below any plumbing. The multiport valve was opened again, and everything looked fine---water is NOT going through there to the waste line.

In fact, the water level is well below the filter, pump, and the end of the waste line, so siphoning doesn't make any sense.

He's coming back with some machine to test the liner for leaks. He doesn't expect to find any.

The concrete patio area around the pool looks fine (no new cracks, no sinking, etc). The grass around that looks fine (no soggy areas, no patches of dead grass, etc.). The pool equipment is housed above ground in a shed about three feet from the pool. The pump runs fine when the water is at skimmer level--there doesn't seem to be any suction loss or bubbles coming from the return line. Of course, it only runs fine for a day, because the water level is dropping so quickly.

Does anyone have ANY ideas? The only think I can think of is an underground plumbing leak, but the water level is too far below any plumbing now for that to make any sense. I suspected a leak around the fiberglass stairs...except that the water is coming out the waste pipe!

I am at a complete loss. I'm a widow with two young kids at home and three kids in college; I just don't have another large chunk of cash to put into fixing it! I was really hoping a new liner would solve the problem! Much to my kids' dismay, I'm considering just filling it in with dirt if this is going to be an expensive fix.

Although I hope someone will write back to say "no worries! This happened to me and it cost me $20 and two hours to fix," I doubt it'll happen. But I'm crossing my fingers!!

Ideas??

Thanks in advance,

Mari

[Pool Clown]

Hi Mari, Does it leak when the pump is off? Or when the filter pump runs? Or it don't matter, it's always leaking.

[quantumchromodynamics]

Based on the information you have given, I can't think of anything obvious that this could be. Here are some questions that will help us diagnose your situation:

01) Do you have a light in the pool? If yes, where is the water in relation to the light?

02) Is there any chance that you put the parts to the multiport in backwards? This would cause the "Filter" and "Backwash" settings to be reversed.

03) Where is the normal level of the pool water in relation to where the water is going out to the street?

04) How fast does the water come out of the waste pipe?

05) Can you disconnect the waste pipe from the multiport?

06) Is there any chance that there used to be a main drain? Maybe it was disconnected and covered up?

07) How many suction lines are there?

08) Where is your underground water table in relation to the normal water level in the pool?

09) What is the coldest that it got where you live last winter?

10) Is water still leaking out of the pool?

Once the water stops dropping, you need to carefully examine the liner at the waterline to check for rips or holes.

[javajnkie]

Hi Mari, Does it leak when the pump is off? Or when the filter pump runs? Or it don't matter, it's always leaking.

It leaks all the time. I haven't run the filter since last week (when the water level dropped below the skimmer), and it continues to drop. It may have hit the level of the leak today though, as the water is at the bottom step and doesn't appear to have dropped more than an eighth of an inch since last night.

[javajnkie]

Based on the information you have given, I can't think of anything obvious that this could be. Here are some questions that will help us diagnose your situation:

01) Do you have a light in the pool? If yes, where is the water in relation to the light?

No light.

02) Is there any chance that you put the parts to the multiport in backwards? This would cause the "Filter" and "Backwash" settings to be reversed.

I just checked and everything looks normal. The pool guy had it apart a few days ago too, and didn't mention any problems.

03) Where is the normal level of the pool water in relation to where the water is going out to the street?

Normally, they're at about the same level.

04) How fast does the water come out of the waste pipe?

It seems to be a slow trickle right now. But before today, it was pouring out rapidly. The volume of water coming out was MUCH more than...say...turning the garden hose on full blast.

05) Can you disconnect the waste pipe from the multiport?

Yes. It still drains. :/

06) Is there any chance that there used to be a main drain? Maybe it was disconnected and covered up?

hmmm... this is a possibility. I didn't see any evidence of one when the liner was being replaced, but that doesn't really mean much. How would I tell? (haha! Besides a leak pouring out of my waste line!)

07) How many suction lines are there?

One, plus the skimmer.

08) Where is your underground water table in relation to the normal water level in the pool?

The water table is definitely below the normal water level. I only know this because ten years ago, we looked into digging a well. Although not a scientific measurement, I'd say it's probably still lower: I live at the top of a hill and haven't experienced a soggy grounds or, my gold standard, a damp basement.

09) What is the coldest that it got where you live last winter?

20s

10) Is water still leaking out of the pool?

yes, although it has slowed down significantly as of this morning. Probably because I only have about 8000 gallons left!

Once the water stops dropping, you need to carefully examine the liner at the waterline to check for rips or holes.

I'll go wade in it this evening as soon as I'm off work and see what I can find.

Thanks so much for taking the time to respond! I hope my responses sparked some solutions...

~Mari

[quantumchromodynamics]

Q: How many suction lines are there?

A: One, plus the skimmer.

What does the other suction line go to?

You mention that you live at the top of a hill; is your pool higher than the street where the water is coming out of the waste line?

[javajnkie]

What does the other suction line go to?

It a vacuum port and is plumbed into the waste/backwash line. It's at the same level as the return valve. I don't use it to vacuum and only open it once a year--when I close the pool I use it to speed up draining the water to just below the skimmer. It's not leaking though. In addition to the water level now being about four feet below that line, the plug and gasket were replaced "just in case" when I replaced the liner last week.

You mention that you live at the top of a hill; is your pool higher than the street where the water is coming out of the waste line?

Where the waste discharges *may* be an inch or two below the pool's normal water level, but if so, no more than that. It discharges to the street in front of the house and the pool is in the backyard, but I'm pretty sure they're just about level.

I wish I could give you some key piece of information that makes you go "aha!" but if I have that info, it's just not making its way to the front of my brain.

I wonder if my kids (and the neighbor kids) would ever forgive me if they came home from school one day and found a contractor filling it. If I could get them to take up basketball, it really would make a nice basketball court!

Seriously though, if I don't figure out the problem before it's time to close it, how bad will it be to let it sit empty all winter? I have nightmares about it floating and turning into Noah's arc in my backyard. Or is that just plastic/fiberglass pools?

~Mari

[ps558]

What does the other suction line go to?

It a vacuum port and is plumbed into the waste/backwash line. It's at the same level as the return valve. I don't use it to vacuum and only open it once a year--when I close the pool I use it to speed up draining the water to just below the skimmer. It's not leaking though. In addition to the water level now being about four feet below that line, the plug and gasket were replaced "just in case" when I replaced the liner last week.

You mention that you live at the top of a hill; is your pool higher than the street where the water is coming out of the waste line?

Where the waste discharges *may* be an inch or two below the pool's normal water level, but if so, no more than that. It discharges to the street in front of the house and the pool is in the backyard, but I'm pretty sure they're just about level.

I wish I could give you some key piece of information that makes you go "aha!" but if I have that info, it's just not making its way to the front of my brain.

I wonder if my kids (and the neighbor kids) would ever forgive me if they came home from school one day and found a contractor filling it. If I could get them to take up basketball, it really would make a nice basketball court!

Seriously though, if I don't figure out the problem before it's time to close it, how bad will it be to let it sit empty all winter? I have nightmares about it floating and turning into Noah's arc in my backyard. Or is that just plastic/fiberglass pools?

~Mari

You gotta keep water in the pool or that new liner will be ruined. Have you tried to plug the waste line and see if the water level stays?

Was the multiport gasket glued in the track, they can move if not. Does the handle on the multiport valve have good tension. the spring could bad or broke not letting the valve to seat, very rare but could be.

[mrfixit]

Is it possible that the backwash line is linked in with some weeping tile around the pool? Maybe the weeping tile is picking up the water and you think it is coming from the backwash when it really is coming from the pool via the ground.

maybe try to plug ALL the openings into the pool,after it has been filled back up. This includes skimmer, main drain and returns and if water still leaves the pool, then you know it is not a plumbing issue. If water doesn't leave the pool, then remove the plugs in the lines 1 at a time ( 1 each day) and look for water loss.

Think about it logically, the water can only leave the pool in 2 ways. Either it is leaving the pool directly, (ie thru a hole in the liner or a bad gasket around a return jet) or it is leaving thru the plumbing. the trick is to isolate the 2 from each other and then narrow down where the leak is from there.

And yes, keep the pool filled. If the water level gets too low, the liner will slide from the shallow end toward the deepend and you will have major wrinkles, or possibly a tear in your new liner.

[quantumchromodynamics]

"It a vacuum port and is plumbed into the waste/backwash line."

Why is the vacuum line plumbed into the waste/backwash line? I'm thinking that it is a drain line. If it is a drain line then it has to be higher than the street where the water is discharging.

Based on the information that you have provided, it seems that the water in the pool has to get into the waste line and then go up to get to the street. I don't see how that is possible without a pump.

I think that the water level now has to be about the same level as the street. You say that you are on a hill. It can be very deceptive to try to guess elevations. I think that your pool is probably about 3 to 4 feet higher than you think.

Have you had a chance to check the liner at the water line?

[javajnkie]

Is it possible that the backwash line is linked in with some weeping tile around the pool? Maybe the weeping tile is picking up the water and you think it is coming from the backwash when it really is coming from the pool via the ground.

maybe try to plug ALL the openings into the pool,after it has been filled back up. This includes skimmer, main drain and returns and if water still leaves the pool, then you know it is not a plumbing issue. If water doesn't leave the pool, then remove the plugs in the lines 1 at a time ( 1 each day) and look for water loss.

Think about it logically, the water can only leave the pool in 2 ways. Either it is leaving the pool directly, (ie thru a hole in the liner or a bad gasket around a return jet) or it is leaving thru the plumbing. the trick is to isolate the 2 from each other and then narrow down where the leak is from there.

And yes, keep the pool filled. If the water level gets too low, the liner will slide from the shallow end toward the deepend and you will have major wrinkles, or possibly a tear in your new liner.

Thanks everyone. The pool guy is due here any minute. The store says he's "all mine" today, so I guess he plans to spend the day working on the issue. I'm hoping they did something wrong when they installed the liner, because they already have $4000 of my money and I don't want to part with any more.

It HAS to be a structural or liner leak because it the water line in the pool is 4' below all of the suction and return ports. There is no visible way for the water to be leaving at all. So even if things were messed up when putting the multiport valve back on, it shouldn't make a difference after the water dropped below the level of the skimmer and other plumbed inlets and outlets.

You're all fabulous. Thanks for your responses and efforts. I'll come post a follow up...hopefully by the end of the day I'll know something!

~Mari

[jdunning]

You're all fabulous. Thanks for your responses and efforts. I'll come post a follow up...hopefully by the end of the day I'll know something!

~Mari

Hi Mari,

I'm dealing with a similar issue to yours. Any luck with the inspection? What did the pool company find?

Thanks,

-Josh

[4serendipity]

A few thoughts come to mind with your problem.

1) The liner is not the source of water loss. You will not lose this much water through the liner and even if you did it would saturate the area around the pool itself and not find its way to the backwash line.

2) Pool elevations mean little in a closed loop plumbing system. Without seeing your problem first hand it is impossible to say however I can personally attest to the fact that a "gravity drain" can be one of the most elusive and difficult to diagnose pool leaks. The concept is that the weight of the water running down the backwash line in a closed system is strong enough to create a vacuum that will continue to draw water even against the force of gravity.

3) If the water is exiting through the backwash line of the pool, could you not put a valve on the backwash line to stop the water from accessing this point when you are not backwashing? Its a low tech / low cost solution to your problem

4) What is the make and model of your filter? the Tagelus model TA60, TA 80 and TA 100 are INCREDIBLY prone to water escaping through the backwash line where there is negative pressure acting on the spider gasket in the filter head. I have stopped using these filters altogether as a result of this problem.

5) Plug the vacuum line in the pool.

6) Has your plumbing system been redesigned in the mechanical room recently? It almost sounds like someone has installed the pipes wrong in the mechanical room.

7) Find out if you have an equalizer port in your skimmer. If there used to be a main drain you may still have a line that water is able to access through the skimmer. Since the water level is dropping so low your problem would normally be attributed to a faulty main drain, but the lack of main drain is kind of puzzling. The water is below all the suction points but continuing to receed so it looks like a structural issue, except that the water is escaping directly through the backwash line which then points towards a plumbing issue.

I hope some of this information is helpful.

S

[javajnkie]

I'm dealing with a similar issue to yours. Any luck with the inspection? What did the pool company find?

Thanks,

-Josh

Hi Josh,

Sorry for the delay in responding; I've been out of town.

It turns out that the brand new liner had a tear on the floor. Someone suggested that perhaps the pool used to have a main drain that was filled long ago is really the only way I can make any sense of this. The pool guy said he doubted it, but had no idea how it was draining out there--especially since by the time he fixed it, the shallow end was empty and the deep end had only a few feet of water. On top of that, I had even disconnected the backwash line from the pump all together and it was still pouring out until the leak was fixed.

So the mystery remains, but I'm going with the thought that it was seeping through the concrete/vermiculite floor and draining through an old main. I'd love to know!

The pool has been up and running for a few days now, with no problems! I hooked the pump up exactly like I did before, and we're good to go! So for now I'm happy...except for the extra $700 or so I expect to see charged on my water bill. The liner company extended my warranty for the seams and warrantied the patch. I thought about having them replace it completely, but I've already spent so much on water.

Oh! I asked the pool guy about what the previous owners called a 'vacuum port' and told me it drained out the front. It's always been plugged, by the way. I've never used it. Vacuuming from the skimmer seemed like less hassle before I invested in an aquabot. Anyhow, he said he thought it was probably a return line that broke and was replaced long ago. We opened it and it appears to lead no where. It's plugged again.

Did you figure out what the problem is with yours?? Are the issues really the same---the water level being too low for it to be draining where it's draining?

Thanks again everyone! I've bookmarked the site and will definitely be back!!

~Mari

[javajnkie]

Let me apologize first for the length of this post! I'll try to keep them shorter in the future!

The problem is solved, but I'm curious anyway. I figure the more I know, the more I'll be able to prevent it from happening again. In retrospect, I should have known within seconds that their was something wrong. I spent three days trying to fill the pool from my hose immediately after the new liner was installed. After the leak was fixed, it took half a day. :/ *doh*!

1) The liner is not the source of water loss. You will not lose this much water through the liner and even if you did it would saturate the area around the pool itself and not find its way to the backwash line.

I wasn't here when the pool guy came. The manager of the store told me afterward it was a leak in the floor of the liner. I know he didn't do anything to my plumbing, but honestly, I can't find where he patched it. When the manager told me that, I asked how it could cause it to leak from the waste line and he seemed confused (said his guy hadn't told him that's where it was leaking). They seem honest enough, so I'm hoping they gave me the full story.

3) If the water is exiting through the backwash line of the pool, could you not put a valve on the backwash line to stop the water from accessing this point when you are not backwashing? Its a low tech / low cost solution to your problem

I tried that. And disconnecting it from the filter altogether. There has to be a T somewhere in the line past the filter, because it was not being routed through the (hayward) filter.

5) Plug the vacuum line in the pool.

It's always been plugged. See my response to Josh--I was wrong about it being a vacuum line.

6) Has your plumbing system been redesigned in the mechanical room recently? It almost sounds like someone has installed the pipes wrong in the mechanical room.

Doesn't it though!? But no. Hah. I had to actively dismiss the paranoid thought that someone came over while I was camping with the kids, dug up the underground plumbing, and rerouted everything. Everything around here except for the pool liner installation (and follow-up) is DIY these days and I know I haven't touched the plumbing out there! Completely unrelated: I did recently learn (with the help of a great DIY book) how to cut and sweat pipes when a hot water pipe started to leak! Combined with taking a saw to my kids' bunk beds and making two twins, I felt like She-Ra! Ah...it's those little things in life...

7) Find out if you have an equalizer port in your skimmer. If there used to be a main drain you may still have a line that water is able to access through the skimmer. Since the water level is dropping so low your problem would normally be attributed to a faulty main drain, but the lack of main drain is kind of puzzling. The water is below all the suction points but continuing to receed so it looks like a structural issue, except that the water is escaping directly through the backwash line which then points towards a plumbing issue.

Although the problem is fixed, this is interesting and I hope you come back to help me grasp how this relates to things!

I'm not out there, but I have a vague memory of once noticing a closed equalizer port in the skimmer. If it's there, would it only be there if I once had a main drain?! I've never opened it, but could you explain what your line of thinking was here? How could water have been able to access the skimmer through an equalizer port with the level so low and without a main drain? Seepage?

And a final question and note. I'm sorry if this is too far off topic:

I don't believe the end portion (at the street) of the backwash/waste line has been here since 1973. Water exits through a large-diameter white PVC pipe, which just doesn't seem very '70s to me. I've been here for ten years, so I know it hasn't been replaced within that time. As far as I know, it ONLY drains water from the pool.

However, there's a 'matching' PVC pipe extruding from the left side of my front lawn (the pool line comes out the right side). It's not connected to the pool at all, but instead channels water from a drain outside my garage door and maybe from the gutters on that side of the house.

While considering the pool problem, I wondered if maybe a portion of the buried pipe is perforated to allow storm drainage too. Is that common at all?? It doesn't seem to drain heavily during rains, although I don't know that I've ever really paid attention. But the right side of the house is the 'side' with the basement, and during heavy rains, my basement gets wet. It would make sense to me that this pipe would have been designed to do double duty and drain rainwater away from the house (although, if so, it's not performing that function well). But if so, maybe the water coming out of there was seepage from the pool leak? Does that sound plausible? And does it sound plausible knowing that the volume of water coming out of that pipe during the leak was tremendous. It was draining at least as fast as it was filling! I'd be willing to say confidently that the water was coming out of that faster than the water was leaving my hose to fill the pool!

Is anyone still reading? I'm sorry this is so verbose!

~Mari

[4serendipity]

If I have read your post correctly it would appear that the backwash line that you are refering to would in fact be a drainage line in which case your description of water coming out of the pipe as a result of a liner seam failure would make perfect sense. The water surrounding your pool is being diverted away through a drainage pipe that exits your property at a low point well away from the pool. The backwash line from your filter is a seperate line that either discharges at a collection tank or could even potentially could be tied into the drainage line that you are referring to depending on what your local municiple and building codes required circa the time your pool was built.

I hope this information is helpful.

S

[javajnkie]

If I read you right, you agree that it sounds possible? You read my post right, except that it's just an idea. I have no evidence that it is a drainage line--the gutters drain to the ground on that side of the house and as far as I know, the only water that comes out of the line is from the pool.

But I'm glad it sounds plausible! I was really just pondering aloud that it could be that a perforated drainage line merges with it at some point after the filter. Especially because of its location and because it looks like it was probably put in at the same time as the actual storm drain on the other side of the house. Since it doesn't look 35 years old (did they use PVC in the early 70s?), they were probably added later, when they were obviously thinking about drainage issues.

It seemed to me that would explain the mystery--the pool leaks, seeps through the shell, and exits the line. It doesn't explain the immense volume; I'm not a hydroponics expert, but unless the shell and the ground were completely saturated, the flow rate out of the pipe due to seepage should not have exceeded the flow rate into the pool.

Thanks for letting me bounce the idea off on you! I feel really dumb about this stuff most of the time. I never knew how little I knew about maintaining it until I was doing it alone, and I truly appreciate the feedback I've gotten here.

~M