Treatment plant - distance from boundary etc?

[Randomusername]

While reading the brochures for various treatment plant units, I’d been given the definite impression that there were minimum distances from certain features which must be observed.

 

Obviously the requirement to site away from habitable buildings is a requirement in case of nuisance noise and smells - but others are less clear cut. 
 

If for instance I followed the minimum distances specified for the Marsh Ensign, I’d most likely not have space to site anywhere within the boundary - possibly not even within the same county - particularly if I then had to discharge to an infiltration field!

 

However I had a gentleman from a well established local company, whose business is installing such systems, come out to quote recently. 
He raised no such issues and suggested that they would happily install a unit on the very edge of the boundary, close to the road verge and right next to the piped drain that runs along the boundary edge. 
 

Surely a major point of paying out extra for a proper treatment plant is that you don’t have to worry as much about the issues that otherwise restrict the siting of outdated septic systems? So who is correct?

[PeterW]

Nice simple summary of the English and Welsh BRegs and standards here 

[joe90]

Building regs.

 

The Building Regulations 2000 - Drainage and Waste Disposal 2002 edition Part H-H2 Package Sewage treatment Works

The main provisions of these regulations are:

• The Sewage Treatment Plant must be sited more than 7m from habitable property
• The soakaway must be a minimum of 10 metres from a watercourse, 15 metres from a building and 50 metres from a borehole or spring.
• The soakaway must be designed to BS6297: 2007 and all percolation test results must be submitted. 
• The discharge point shall be more than 10m from habitable property
• If the discharge is to a soak away a sampling chamber must be provided before the soak away. These are available from WTE Ltd..
• Soakaway drains must be constructed in the aerobic soil layer, i.e. within 700mm. of ground level.

[joe90]

Ha @PeterW, same source!!, WTE, great minds think alike ?

[ProDave]

The clearance distances are a little different in Scotland.  But they do take up a lot of land and particularly for a soakaway you do need a LOT of land.  That's why you often see a soakaway located under an adjacent field as there is not enough room on the plot.

 

And since you will need building control approval for a new treatment plant, don't think you can quietly ignore the rules, they will want to see the plans that show everything fits within the required distances.

 

The one that caught us out was a soakaway has to also be 10 metres from a road. That left us insufficient space but that eventually led to us being given permission to discharge to the burn.

 

The one that struck me as "most stupid rule" was the distance from soakaway to watercourse.  We had been given permission to discharge to the burn, but via a partial soakaway.  So given all the limits we installed a partial soakaway in the little strip of land in the middle that met all the rules, and from there it is piped in a solid pipe to discharge into the burn.  You would have thought in this situation as it was going to end up in the burn anyway, we would have been allowed to make that partial soakaway much larger, fight up to the edge of the burn, but no that was not allowed.

 

 

[Randomusername]

That’s all fine, as I intend to discharge directly into the covered drain, I fortunately won’t have to worry about the expanses required for infiltration/soakaway. 
 

It’s interesting that the regs make no stipulation for the proximity of the actual unit from certain features, but then the manufacturer guidance indicates the below:

 

 

Although it is headed as “guidance only” it then goes on to state that “these are minimum distances”.

?

[PeterW]

They do it as “guidance only” as local BCOs may allow it to be closer and it also depends on the part of the UK you are in. 

[Randomusername]

8 minutes ago, PeterW said:

They do it as “guidance only” as local BCOs may allow it to be closer and it also depends on the part of the UK you are in. 

I’ll ask local building control for confirmation/clarification. 
 

The man who came round is fairly local and so I’d expect him to know, so that’s a good indication that I’ll be able to site close to the boundary, hopefully. 

Edited December 12, 2020 by Randomusername

[joe90]

4 minutes ago, Randomusername said:

I’ll ask local building control for confirmation/clarification.

Yes, they are the ones who will sign it off.

[DragsterDriver]

I guess there must be leeway if you physically can’t site the treatment plant that distance from the dwelling

[ProDave]

34 minutes ago, DragsterDriver said:

I guess there must be leeway if you physically can’t site the treatment plant that distance from the dwelling

Probably but BC here only seem to make exceptions in extreme cases.  e.g. a neighbour was allowed to install a treatment plant about 3 metres away from a watercourse.