What size attenuation tank do you have/have planning for?

[Happy Valley]

Interested to hear what size attenuation tank you have. 

 

This is purely for rainwater/surface water in England. 

 

We have a roof size of about 200 sq m and have been advised that we will require a 16 cu m tank which seems rather excessive.

[joe90]

Ha, our building inspector (who was a practical chap) told me I needed to provide a soakaway and I just laughed, explaining that on our solid yellow clay it would just fill up and stay full, currently all rain water from the site went into a ditch at the bottom of the garden so we just directed it there 👍. Result.

[PeterW]

57 minutes ago, Happy Valley said:

We have a roof size of about 200 sq m and have been advised that we will require a 16 cu m tank which seems rather excessive.

Based on what ..? And attenuation to where ..? A soakaway or to a storm drain ..??

Who’s done the calculation ..?

 

[nod]

We are pretty much the same as Joe on our next one 

Boulder clay We will run 75 meters to a dyke 

It would have cost more to put a tank in 

[Happy Valley]

55 minutes ago, PeterW said:

Based on what ..? And attenuation to where ..? A soakaway or to a storm drain ..??

Who’s done the calculation ..?

 

 

It goes to a sewer in the road, professional company did the calculation based on 1.10 l/s

[BadgerBadger]

Our roof area is slightly larger, and we're looking at 19m3... so broadly comparable, but big!  Did you do an infiltration test?

[PeterW]

1 hour ago, Happy Valley said:

 

It goes to a sewer in the road, professional company did the calculation based on 1.10 l/s

Is that the limit from your waste water provider ..? And is that M10-D or M100-D..??

[Happy Valley]

17 hours ago, BadgerBadger said:

Our roof area is slightly larger, and we're looking at 19m3... so broadly comparable, but big!  Did you do an infiltration test?

 

OK so not an unusual size. No infiltration test has been carried out.

[ToughButterCup]

20 hours ago, Happy Valley said:

Interested to hear what size attenuation tank you have. ...

 

We have a water garden for each side of the roof (same area as yours) - each the maximum size of cattle trough (no idea what size that is) , the overflow of which goes into a sand bed filter, and then into a pond. That pond spills over into a bank of trees and a thirsty fence line : Alder, holly, blackthorn, privet, very old oak trees. Anything else trickles away into Great Crested Newt Central. 

 

The BCO took one look at it, sucked his teeth, grinned and put a tick in a box.