Groundwater coming into pool/floating liner.

[Pughball]

Hey everyone,

I am positively baffled. We knew we had water coming in and pushing against our vinyl liner pool last year, with a significant rain it would swell out and then a day or so later drain and effectively resets itself wrinkle free.

This year, after any appreciable rain, say an inch or more, not only does the liner float but the pool absolutely FILLS with dust/dirt. It doesn’t affect the chemistry at all, other than using slightly more chlorine but the pool is FILTHY!

behind the pool is being developed and all the water drains at a low spot behind our fence. Our pool sits about 20-25 inches above that low spot so I know it isn’t coming in over the concrete decking. It HAS to be finding an entry point within the pool, I assume. After running the filter 24/7 for about 5 days it goes back to crystal clear. But I need towash our cartridges 3 times a day for all those days and that just ain’t practical. Also, the pool is ugly and unswimmable until the filter can get all the dirt out.

how can this POSSIBLY be getting I to the pool?

My only theory is so much groundwater is coming in behind the pool with nowhere to go they it cascades up and over the liner where it meets the coping. I’ve never seen it happen but I can’t think of any other entry point.

We don’t lose any appreciable water to a leak without rain. I imagine standard amounts of evaporation. Maybe an inch or so a week in 90 degree heat with full sun all day.
Im open to any ideas here as to how water is getting in, how I can keep it out.

 

[duraleigh]

It sounds like you have a tear in your liner. When the groundwater subsides, the liner is tight enough to the frame to seal it up mostly so you don't notice a small water leak, if any.

When it rains, however, that tears lifts off the frame and the pool water is then free to transfer outside the pool and the outside groundwater is free to transfer into the pool.

Finding that (tear, hole, rip, leak) is essential and then you should make plans to eliminate that groundwater as well.

 

[Pughball]

So how do I go about finding that tear/leak if it’s this filthy whenever there’s groundwater hahaha

and the liner is only one year old, shouldn’t be that fragile no?

 

[duraleigh]

1. Leak detection company

2. AS the groundwater subsides, I believe your pool will leak down to the elevation of the leak. I am not completely positive that will work but I have no other idea.

 

[Pughball]

1. Leak detection company

2. AS the groundwater subsides, I believe your pool will leak down to the elevation of the leak. I am not completely positive that will work but I have no other idea.

It’s already done this once this summer and it never leaked down at all. Hmmmm. Guess I’m searching for leaks when it clears again.

 

[Rich D]

It’s already done this once this summer and it never leaked down at all. Hmmmm. Guess I’m searching for leaks when it clears again.

Or... After it clears, jump right in there with a mask next rainstorm and see where the dirty water is coming in. Hopefully it will be a lightning-free storm..

 

[duraleigh]

Well, I doubt that will work. I think that once the groundwater recedes below the leak, the leak stops.

 

[Rich D]

Well, I doubt that will work. I think that once the groundwater recedes below the leak, the leak stops.

Doesn't the groundwater come back up with the rain?

 

[Pughball]

Or... After it clears, jump right in there with a mask next rainstorm and see where the dirty water is coming in. Hopefully it will be a lightning-free storm..

It’s too bad the rains keep coming at 3 AM. It’s hard to believe that a hole/test that is allowing that much dirt in seals itself as the water recedes. It definitely makes the most sense tho. Time for the professionals I guess

 

[TT030]

Could there be a hydro-static valve in the main drain that is opening when the water table is high? I know they are more common in gunite pools, but I wonder if that is a possibility if a tear can not be found in the liner.

 

[Pughball]

No hydrostatic valves as we don’t have a main drain. We’ve been two full days now and the water has made next to no improvement. It will clear, with time but we lose a heck of a lot of useable season like this...

 

[Rich D]

I would suggest getting the floating liner (ground water issue) under control immediately. That will allow you to keep the pool clear (and useable) and find the leak much easier. This will need to be done to prevent further issues anyway so you might as well do it now.
Do you have pics of the excavation and install?
Do you know if they put in any kind of drainage?
How deep is the deep end?
They should have at the very least put a drain on top of the collar to a sump so you could pump ground water out to change the liner.
There are a few options as far as dewatering goes. You can drive a few point wells and pump it down However these have a tendency to clog up over time and you can not easily adjust how low you keep the ground water around the pool so the pump will run a lot more than necessary. The more bullet proof and versatile method would be a sump pit dug down to just below the bottom of the pool elevation. This will allow you to pump down to whatever elevation you need. You might only need to pump down to 4' below finish grade to keep the liner from floating but you can pump all the way down if you need to replace liner.

The best option is if you can get a gravity drain out to daylight. Or even tied into the street drainage if allowed. You could put a gravity drain in the sump at the lowest possible elevation and have to option to be able to pump it down as well for liner changes.

I would get a few estimates for this. You can try a few pool companies but I have found most do not fully understand how to properly dewater a site. Your best bet would be a excavation company.

 

[Dtkokay]

Does your pool have an overflow? If so, is that overflow plumbing connected to any of your yard drains?