Another ground water issue

[mbasden]

Hi all,

We're in the process of installing a (15'x34') fiberglass pool. Half way through the dig everything ground to a halt. The spring water table on our property is sitting around 48-50" depth while the pool depth is 3'6"-6'6". It has been fairly wet lately with snow and rain. We're not clear yet how much of this is purely water table vs run off or ground water from neighbouring properties which are slightly higher than ours.

The installer met with us and their recommendations were:

• to raise the grade around the pool 1'6"
  • which would require a french drain around the pool to ensure there are no water issues with the house foundation (walkout basement), and
  • leave us with 2 steps to get up to the concrete decking, or
• change the pool to a shallower pool (~5` depth),
• otherwise they won't warrant the install.

Needless to say we're not impressed and neither option is truly a solution, they are just easier options for the installer to get the work completed.

They do install a pool sump/dewatering well/groundwater shaft, but they don't seem to think that's adequate but haven't articulated why (unless they're just trying to get out of their warranty). What's also not clear is how low the summer water table is expected to be.

Today we pumped it out (still some remained) and we're to send a photo to them tomorrow morning to see how much returned (like a well recovery rate). But given that it's been so wet, and is expected to rain for the next few days this won't be a good measure.

If we overdig and lay crushstone underneath, install the pool sump and a hydrostatic valve should that be sufficient to mitigate the risk of popping the pool in the wet season?

Thanks in advance for any input!

Cheers,
Mike

Below is a photo of the water that has collected since Thursday (photo taken on Monday).

 

[Casey]

That's a lot of water. It's kinda hard to truly know what the hole will look like with rain in the forecast. Maybe halt the install until the weather clear and you can see just how much it fills with no rain in the forecast. If worse comes to worse n you really want your chosen pool, having it raised is an option... obviously not for your wallet but it's an option.

 

[Jayphil]

That look like a lot of water but I not and expert and it is difficult to judge by picture so you might want to have another expert go on site (beside you pool company) to give you advises.

I am not sure what are you criteria for your pool but I have a 4,5' pool without deeper side and it is perfect. 6' you can still not dive in so only feet first. I am able to jump in my 4,5' pool without a problem and I am also able to swim. Also there is no slop which make it better for playing in the pool (volleyball, basket etc. ).

Regardless of your choice you should try to overbuild your solution to get the water out... better be safe than sorry later.

 

[Noreaster]

I actually think you are lucky the dig happened now and i would not write off the water as being a high spring water table. If this were installed in the late summer - then the water rose the next spring, you may have been screwed. Curious what the inflow rate is on that. It may be too much for a a sump to keep up with.
Its easy to spend someone else's money, but i would favor raising the grade - even if this cleared up in a month.

 

[cowboycasey]

A sump pit should work just fine but if they will not warranty the pool it will not matter... Ask them specifically why they will not put in a sump pit.. You can actually do a sump pit now and install it and see if it will get all water out.. if it does you are good to go, if not then you know you will need to raise the pool deck a foot or so...

Buy a sump pump, plug it in with a hose attached and throw it in the middle.. does it take the water away and keep it away?

 

[mbasden]

Thanks for the replies.

I agree that we're lucky to have dug in the spring and caught this during the high seasonal water table. The installer pumped it out on Monday and it slowly started to fill again. We did have more rain/snow in that period but here's what it was like the following morning.



So it was down about 8-9" from the previous mark. The level has now stabilized about 6" below the mark even after more rain yesterday.

The installer also came out yesterday with someone from another pool company. He said he didn't need to meet with us, but again spoke to my wife and said they need to raise the grade 2' now instead of 1'6". The opinion from the second pool guy was that changing to a shallower pool was also not an option.

As you can see from the photo, we have a walkout basement. So raising the grade would cause water to run back towards the house and really complicate things for the deck and walkout.

 

[ajw22]

I would have pool well points dug around the pool area and pumps put in them and then see if that manages the water problem.

@jimmythegreek what would you do?

How and When to Install Wellpoints

Swimming Pools with High Water Tables? When you think of building pools, you think of dirt. When you think of building pools in the South, you think of

cpoclass.com

 

[Jayphil]

Thanks for the replies.

I agree that we're lucky to have dug in the spring and caught this during the high seasonal water table. The installer pumped it out on Monday and it slowly started to fill again. We did have more rain/snow in that period but here's what it was like the following morning.
View attachment 402885
View attachment 402886

So it was down about 8-9" from the previous mark. The level has now stabilized about 6" below the mark even after more rain yesterday.

The installer also came out yesterday with someone from another pool company. He said he didn't need to meet with us, but again spoke to my wife and said they need to raise the grade 2' now instead of 1'6". The opinion from the second pool guy was that changing to a shallower pool was also not an option.

As you can see from the photo, we have a walkout basement. So raising the grade would cause water to run back towards the house and really complicate things for the deck and walkout.

Did they explained why it is not an option? I believe this is not solving everything on it own but a shallower pool with proper drain / sum pump setup together can be a solution. Much better vs only drain/sum pump or raising the pool and messing with water going toward the house...

 

[jimmythegreek]

Are you dead set on a fiberglass pool? A liner pool can take that water table. I wouldn't chance the proposed pool on this PB. There is a solution to install that pool but it's gonna cost the PB money he didn't plan on spending.

 

[PoolStored]

@jimmythegreek knows his stuff. I'd listen to him.

 

[mbasden]

I'm not dead set on a fiberglass pool, but given the stage of the build we're in, our options are limited with this PB. I'm not sure that we can find another PB to install a liner pool but now but thanks for setting me in that direction! @jimmythegreek Any more details on what the solution would be, even if this PB doesn't want to do it? Thx!

 

[jimmythegreek]

You would need the pool to be set on a thick bed of 2" stone that septic tanks are normally set on. This would be after the muck in hole was de watered and removed. You would need at least one but preferably 2 sump stand pits with standby sump pumps tied into underground electric and a drainage line. You also need 2 relief valves similar to what concrete pools use, the second one is just cheap insurance. I have 3 sump pits on my own pool and it's a liner pool. They said it can't be built so I did it anyway.....kids make you do crazy stuff and spend all kinds of money

 

[mbasden]

Well, sadly we're going to tell the PB to fill it in and give us our money back. He completely disappeared and told us we'd have to figure it out on our own. To say we're disappointed and frustrated with this guy is an understatement. It's been a month and nothing has happened. He hasn't given us any advice on where to start, who to contact or how this can be addressed aside from raising the grade of the yard, which absolves him of all liability and puts it on us. I'm not willing to accept that. I know we'll have issues raising the grade that much, so it's not an option.

Thanks to everyone for your time and consideration with this thread. I do appreciate your opinions and insights.

Cheers,
Mike

 

[Lanzz]

Jeez, Mike, i wish there was a better outcome. But that pool builder doesn't sound like the guy you want to go into battle with. I hope you find an alternative soon.