# Forum Home Renovation Pools, Spa & Water Features  Ground water drainage fibreglass pool?

## hildahoop

I have only recently moved into a new house, we are not far from the coast in the sand belt area in Melbourne. We signed up for a fibreglass pool about 2 weeks ago, I have been clearing the old decking from the area where the pool is to go. I have been suprized to find the soil is not sandy at all and is more like estuary mud/clay peat.
With all the recent rain the soil is very very wet. I am becoming worried that this may cause the pool to try and pop out or at least cause the releif valve to operate which I assume fills the pool with mud.
Sould I hire a ditch witch and run a few ag' pipes round the area near the pool? If so should they be deeper than the pool or is 600mm enough to take away the amount that would cause a pool popping incident? Behind my house is a deep council storm drain just cut into the soil could I head the pipes that way or do I have to connect with the rain water pipes?
I probably won't attempt the job myself but I like to do my reasearch before I ask a plumber or the pool people for their quote.
Thanks for any advice

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## Geoff2005

The only time I 've heard of this is when the pool is emptied or partially emtied.  
Your idea or running the slotted ag pipe to a drain is good. Make sure you use the stocking matreial to cover the slotted areas of pipe. 
When my pool was installed I put a pvc pipe with tee and two 300mm slotted stubs, covered with stocking, in beside the deep end of the pool. The bottom of the pipe has the tee near the lowest part of the pool. The top of the pipe has a cap and is under a paver, so if need be I can check static water level.

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## GeoffW1

Hi, 
That valve on the pool bottom is designed to operate when the pressure of groundwater ouside exceeds the water pressure inside, that is, when the groundwater level around is markedly higher than the water level in the pool. 
The weight of the pool shell is also a factor, plus the weight of any concrete surround sitting on the lip of the pool. 
If there is persistent groundwater in the area of the pool, ask for a standpipe, or dewatering pipe, to be installed at one end, with a grating on it in the pool edging. The bottom of this pipe should be connected to at least one ag drain under the pool shell, which is commonly bedded in sand, or a sand-cement mix.  http://www.swimmingpoolkitsdirect.co...tructions.html 
The purpose of this standpipe is to be able to check on the level of groundwater, and to be able to drain it with a small pump if you must lower the pool water level for maintenance. 
Cheers

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