She Who Is All built the house, I joined up 6 years later.

So of course all failures of appliances, fixtures, etc are my fault.

In ground indoor pool. I have been primary technician for over 15 years, learn as I go.

So, new heater. All good. No leaks, heats perfectly.

3 days in, notice water level is dropping a little. Great, another leak in one of the three light housings. Top off water, all is good.

Not so much. Next day, water is eight plus inches low. Like approaching 10,000 gallons lost. No detectable leaks in the equipment. Shut off heater and pump, open the retractable cover to remove stress on it, put the floating cover on. Go berserk looking for the 10,000 gallons in the basement. (Idiot architects put the plumbing and equipment inside the house envelope not in a separate structure) Can’t find the water.

8 hours later (pump has been off) water level has not changed. Has to be in the pressurized pvc.

All the pvc is under the concrete deck inside the room or underneath the pool (deep end drain).

25 years old. Dig it up and replace all the pvc?  Needs a new vinyl liner right now.

First world problem.

Get some leak test dye and see if you can find it.  Also if possible isolate drain(s) and skimmer line(s) by shutting off valves and run for a while, see if any particular one is leaking down.  If it leaks all the time while running it seems like it would be in the returns somewhere.  Depending on your shutoff/valve setup you could possible just isolate and cap off whatever line is leaking.

8 “ and 10k gallons lost ?
That’s a big indoor pool.

Water was already below skimmer and pump was sucking air. I had installed isolation valves so I shut off the skimmer. Pump resumed proper operation. But jets were already about four inches above waterline.

We have NEVER had water level drop 8” in a day. Lots of leaks over the years.

If you're going to replace the liner, have a leak detector come pressurize all the plumbing lines before they put the new on in in case it needs a new skimmer or steps or something.

Guessing. 18x42 and it dropped from 2” over the top step to 1” below the next step down.

Lots of water missing. Like flood the basement quantity.

Leak detection company time.

I had a cracked pvc tee in my return lines, lost a shit load of water overnight, several inches.  Had a leak detector come out and locate it.  Cut the concrete about 2x2, dug down, repaired it, filled the dirt and poured new concrete.  Sucks.

Leak detector guy was about $500.

Check spider gasket in filter. They fail.

Go to troublefreepool.com. That is massive water loss.

enjoy your new skatepark.

I have had that gasket fail. Have spares and a new multiport valve assembly on hand because of that. It’s not that gasket. All the equipment is inside the house above the unfinished basement so where the hell did all that water go?  And why did the leak stop when I shut off the pump and closed the drain and skimmer valves?  8+ inches in a day?!?  Has to be in the pump pressurized piping somewhere after the pvc goes over the foundation wall or I would have a flooded basement.

Check your waste line to make sure the spider gasket in the multi valve is not bad, causing a portion of water going through the filter to go out the waste line instead.  Had this happen to my inground last year and lost quite a bit of water overnight.

If not that, then I agree with what others have said and have a leak detection company come out and test the underground pipes.  We did when we bought our house knowing there was a return leak somewhere.  There indeed was, but I never fixed it.  We just had trenches cut into the concrete and new plumbing installed, then put pavers in the trenches.  It's not perfect, but it was a bunch cheaper than new concrete or fixing the original leak, which likely wasn't even the only one.  

If they find the leak in the bottom drains, it might be best to just have it capped at the drain itself.  Someone did that to our pool years ago.  That pipe is under the pool and a royal cock to get to.  We haven't had any circulation problems without it.  When we had a new liner installed a couple years ago, we had them remove the drain.  

Our pool is about 38 years old and was severely neglected for the last several years.

You sound more competent then the people I know who run a manufacturing plant. You got this! Calling in people is huge money. Take breaks and a day or two to sleep through the process. Try not stress out, but if you do it's because you are solving a single step in a bigger project then one person can possibly do in a day. Then relax and get the next step done.

all gd'ers i know live in a 35000 sf home, and have at least a 1/2 million gallon, indoor, in-ground saltwater pool to swim in.  (for times they don't to hang out in the grotto) you should already know this.

Waste line is inside the equipment room with the pump and heater inside the house above the basement. And I installed a cutoff ball valve in that line years ago  because of spider valve leaks.

Wife spent all day trying to call service techs. Looks like I teach myself more pool shit.

If you need help feel free to message me, send me pics, etc. And I'll try my best, I've been where you are and I do believe you are right, it has to be in an underground pipe

Remove the eyeball fittings see if you have less water loss or are able to run a temp line from filter to pool and plug returns



Another crazy idea, I have seen where main drain was turned into the return when all fails, and you won't have to worry about entrapment (VGB)

Did you happen to have a heavy rain and hydrostatic valve pop



But I guess the basement would have flooded unless the pool is incapsulated in its own vessel

You mean slip and slide, OP posted pool is a vinyl liner

Unless you happen to have an indoor Olympic-size swimming pool, you did not lose 10,000 gallons overnight from 8 inches of water loss.

An 18-ft x 42-ft pool losing 8-inches of water is roughly 500 ft.³ of volume, which is approximately 3,700 gallons.

Yes, that's a lot, but it's nowhere close to 10,000 gallons.

hang on.  

frequent and occasional heavy rain in the last few weeks and the ground is saturated.  

there is a valve in the deep end floor drain?  

if this is the failure, why did the water loss stop when I shut off the pump and closed the valves on the intake side of the pump that come from the skimmer and floor drain?  wouldn't it continue to lose water?  the pump puts suction on the floor drain.

the pool is in its own separate building that shares a wall with the house that is built as an exterior wall.  the pool sits inside its own foundation walls but there is no basement or slab under it.

I was going very rough estimate.  lost about 1/3 of water depth on the shallow end.  more like 12" loss.  deep end has sloping walls so only the center about 8x8 ft area has a flat bottom.  I could do the math but not worth it.  

a lot of water went somewhere.  need to figure it out.

we've had almost continuous leak issues from the three light housings.  mostly very small and slow leaks.  like 2" over a week.  this was more like 10" in less than a day.  almost 12".  

do the jets leak right where they penetrate the liner?  

water level has not dropped in over 24 hours since I shut off the pump.  there are separate ball valves for the skimmer and deep end floor drain, those are closed.  the jets are now about 4" above the waterline.  trying to wrap my head around likely leaks.  

local pool service outfit installed a new liner about 4 years ago, it pulled out of the aluminum channel and is drooping, just past the 3 year installation warranty.  he's trying to say we had chemistry problems and that's why they can't get the liner problems resolved.  original pool company fucked up the install, the concrete deck is cast not square and not equal length sides making the motorized cover not work correctly since new.  original pool company literally duct taped phone book sections to the aluminum drum the cover winds onto, to make one side retract faster than the other.  the next guys used 1/2" thick rubber sheet instead of phone books to do the same thing.

about to recommend to wife that the entire pool be ripped out, new piping, new walls, new stairs, new liner.  build a new shed next to the pool and put all the pool equipment there and not inside the house.  tired of the constant bullshit.  goddamn equipment room is so small it's impossible to do any kind of maintenance.  

whomever decided that a 1hp pump and all the filter/heater/valving should be inside the house and above the basement needs to be tracked down and have his balls coated in honey and then staked out spread eagle over a fire ant nest and forced to watch The View marathon.

Is the liner floating

Liner is tight against the walls. Drooping about 4” along a roughly 4 ft stretch of deep end wall. Water level when normally filled is about 4” below the lowest point of the drooping liner.

Abandon piping in place start over

Best $500 I ever spent.

I chased a pool leak for months.

Finally broke down and hired a company.

I wish I would have just hired them from the start.

There are other options.  We sub in leak detection guys when we can't find leaks in domestic water services.   They can help you.  There's a microphone they can insert into the lines, there's corelation equipment they can use, there's listening from the top with sensitive earphones, they can charge the system with helium (I think it's helium) and use a detector at ground level. Reach out to local water parts distributor, excavating contractor, pool company or water dept

but if the pool company didn't use the correct glue for underground , you might be replacing all the fittings

Mine leaks.

Rather than paying someone to find the leak, I just had my landscape guy run a pipe to the flowerbed behind the pool and now I have a fountain that refills the pool via the irrigation system timer.

Why address your problems when you can over-compensate for them?

Isn't that what GD is all about??

Ours evaporates 1-2" of water every couple.days this time of year.   Once the night temps are hotter it will stop. I thought it was a leak when we first noticed it and had American Leak Detection come check it.   They said its normal

Because sinkholes?

Nothing says "Ichabod" (the glory is gone) like scuttling an in ground pool

I won't do it again,  it sucks...and it keeps reminding you how bad it sucks every time you look at the filled-in hole that was once your pool

I'll NEVER buy a house with a pool, evar again

OP, call the people that replace liner and have them check. I’ve had an in ground pool for 30 years. Best investment ever. Just takes some work.

Leak detector guy is scheduled for 2pm tomorrow.

Decision time when he finds it.

Where was it?  I have a die kit and found a few myself. But I have one now I can’t find. May break down and call somebody.

One other trick is shut off pump and let it drain down to the leak. As mentioned skimmer, returns, lights are common. Or a liner hole. But op isn’t losing water when pump is off.