Soakaway recommendations

3 Dec 2007
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United Kingdom
I have to build a soakaway for the rainwater from our new extension (flat roof approximately 28m²). The soakaway will be around 6m from any building, the ground level here is approximately 0.7m lower than the ground level where the buildings are (ie, the garden slopes away from the house by around 70cm).

My problem is that the ground is very heavy clay (yellow/grey). Even after digging down for around 1.2m, it is still heavy clay. The house was built in 1974 and like all of the others on the estate, the rainwater is discharged into the foul drain (sewer).

However, the BCO insists that I cannot discharge the rain from the new extension in the same manner and a soakaway is a must.

Any suggestions as I just cannot see a "typical" soakaway working in this clay soil?
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Yep, he brings a whole new meaning to the word "stubborn". I could always do as he says, get it passed off & then change it to discharge into the sewer with the rest of the house, but I'd sooner do it "right" (if there is a way to do it "right" given the ground conditions).

I have heard of water reclaimation systems etc, but I simply don't have the money to go down this route.
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Problem is he IS the senior guy there.... :( He is insisting that because the plans that I submitted (full plans approval) state that a soakaway shall be used AND my local water authority (Severn Trent) now forbid the discharging of rainwater into the sewer, I HAVE to use some sort of soakaway.

What would you folks expect to be done in this situation? Is it still permissable in certain circumstances to discharge rainwater to the sewer???

I was in a similar situation a year or so ago and the bottom of the soakaway was clay but dry. The clay started about 600mm below topsoil. When the BI came to see the soakaway, some of the sandy/stoney soil from the upper layer had fallen into the hole, which somehow was spread around the bottom. The BI looked in and said " I see you've gone through the clay layer. That's fine, carry on"
After 12 months no problem. I assume that the soakaway is "doing what it says on the tin"
How senior is he, I'd be gobsmacked if the top man was inspecting house extensions! The regs are actually a guide, anyhoo if a soakaway does not work following a test or it is impractical to dig down to a depth where it does work ask him how you should drain your extension.
speak to your local water company cos at the end of the day its them that own the drains/sewers and they will tell you if youre allowed to discharge into the mains.
i had the same problem but i argued that building regulations state the soak away must be 5 metres away from the dwelling but also 5 metres away from a road which i dont have the space to do so after a little more discussion they allowed me to go straight into the drains. i would nt have minded using a soakaway but both my neighbours houses discharge into my gutter as its a terraced house and i wasnt going to have 3 houses discharging into my small garden
It is unfortunate, but many sewage treatment works struggle to cope with the additional burden of surface water entering the system. It results in MASSIVE pollution incidents as storm water overflows direct the excess sewage/surface water mix into our rivers and streams.

Have you considered the Crate and Vaulted drainage systems now available? They may solve your problem as they provide a massive underground storage area which allows the water to soak away slowly over days instead of immediately on the rainy day.
Of course if a natural occurence like Moles :eek: were to dig from the soakaway to the side of the foul water manhole :eek: who could legislate against them ...David Bellamy :LOL:

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