Deep Bore soakaways (prev RWH IBC and building standard)

[Sjk]

Hi all,

 

Need some help, my build needs a RWH for SuDS, if I use IBC tanks, in a DIY arrangement am I going to have problems getting it signed off? 

 

Many thanks in advance 

Edited July 6, 2018 by Sjk

[Jeremy Harris]

Depends on what arrangements you have for ensuring that the surge runoff tank is always going to have enough spare capacity to absorb a very heavy shower.  If your IBCs are full, where is the water going to go?

 

We have 20 off 196 litre membrane-wrapped Aquacell crates buried under our drive as a surge tank, and that drains over a period of around 24 hours through a permeable layer of soil.  BC were happy with that.  The critical case is winter, when water usage from any rainwater recycling system may well be low, so there may not be much reserve capacity, meaning that the tanks would not work with regard to SuDS.  I'm pretty sure you can't really include rainwater recycling systems as part of a SuDS system, without an additional surge tank and drainage system.

[Sjk]

Thanks, I will speak to my consultant who is due back from holiday tomorrow.

[Sjk]

Due to site constraints, I have been told to investigate a deep bore soak away. 

 

Does anyone know if they need to be a minimum distance from the property? 

[Gone West]

We had a deep bore soak away drilled eight years ago and the BCO wanted it at least 5m from the house. It went down 47m and turned into a well, but that's another story.

[Triassic]

Some planning department dont accept that deep bore soakaways meet Suds. Might be worth checking.

 

for example Norfork CC said.

 

 With regard to Sustainable Drainage (SuDS), currently we would not see deep infiltration or borehole soakaways as infiltration systems to meet the requirement as SuDS. Whilst they can provide important groundwater recharge via infiltration at depth it does not mimic the natural drainage system as would shallow
infiltration. We would only expect it to be used as a final option for the location of discharge of surface water on a par with a sewer.

Edited July 7, 2018 by Triassic

[Sjk]

Thanks, I thought it was a non starter but having to dance around a bit.

[PeterW]

Is this because of a clay soil..?? Or a space issue ..??

 

You can bury ibc tanks if you are careful and get the ones with steel cages and plastic pallets. They need to be encased in concrete too but that shouldn’t be a problem if you get them deep enough. 

 

The issue you will have is that you’re using RWH as a surge prevention system and the regs don’t really cover that well - RWH is covered by a voluntary standard (BS:8515) and there is a lot of good stuff here (ignore that it’s a PolyPipe system, it’s the principle) and then the Building Regs go into the drainage and attenuation part of SuDs. 

 

If you can post a site plan and the issue we may be able to help. 

[Jeremy Harris]

We had to deal with RWH not being permitted as a suitable means of complying with SuDS.  The question asked was "What happens when there has been a prolonged period of rain and your RWH tanks are full?"

 

The only answer in our case was to fit a SuDS compliant drainage system and forget about using RWH, as the cost of both was just far too high.  We're on clay and the cost of our surge storage and slow drainage system was pretty high, even though I managed to buy twenty Aquacell crates for next to nothing.  IIRC, we still ended up paying around £2k for the drainage solution, not including the more expensive permeable paving we had to use for the drive.  Had I paid full price for the Aquacell creates then the prices would have been at least £1k more, I think.

 

It was one of those things that cost more because I didn't think about it during the initial ground works stage.  If I had then it would have been a lot easier to fit the tanks etc then, rather than later, after the house was built and we had building control on the case.

[nowtie]

On 07/07/2018 at 09:20, Gone West said:

We had a deep bore soak away drilled eight years ago and the BCO wanted it at least 5m from the house. It went down 47m and turned into a well, but that's another story.

We're looking at deep bore soakaway and worried about it turning into a well too! I'm guessing no soakaway then?

[Gone West]

51 minutes ago, nowtie said:

We're looking at deep bore soakaway and worried about it turning into a well too! I'm guessing no soakaway then?

Correct, but we did have a well, which we used for watering the garden 😁. Instead of the deep bore soakaway we installed a reed bed system, because we needed a solution quickly for the BCO. We later removed the reed beds when the sewage treatment plant manufacturer improved the outflow readings. This was all in 2010 so I guess things have moved on a bit since then.