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Posted: Wed Sep 15, 2010 1:01 pm
by turningtim
We have have a house (build 1960's in half an acre) on a steep site, having removed the willow tree that was 8 feet from the back of the house its all got a bit wet!
Can I build and land (french) drain and join that into the existing sewer via an underground tank to catch water for watering the garden (not planning to run that back to the house for grey water) so just the overflow runs into the sewer. I was planning do bring the gutters into the tank as well.
how big a tank should I be looking at?
Ive checked and all the down pipes from gutters, and the sink, bath, loo etc eventually end up in the same sewer which I guess is "wrong" these days but must have been OK in the past
Posted: Wed Sep 15, 2010 2:38 pm
by GB_Groundworks
no you can't,
if you are on a combined system then with permission you might be able to discharge surface drainage into it bbut underground drianage will have to be directed to a large soakaway/attenuation cell or a holding tank for grey water use,
klargester and others do the rain water tanks etc and do them in many sizes from about 1000 litres up
a willow tree can take about 2000 litres of water a day out of the ground!!
Posted: Wed Sep 15, 2010 5:20 pm
by jonnyboyentire
Now you know why the willow was there!
Posted: Wed Sep 15, 2010 5:41 pm
by turningtim
Thanks guys,
I'd guessed thats why the willow was there, i was quite fond of it, but more fond of my foundations! :laugh:
Posted: Wed Sep 15, 2010 9:52 pm
by DNgroundworks
re-plant the tree futher down the garden 
Posted: Wed Sep 15, 2010 11:09 pm
by jonnyboyentire
land drain to a willow meadow?!?!
Posted: Thu Sep 16, 2010 3:05 pm
by turningtim
Re-plant the tree?? how do I stick all those logs back together?? :p
Seriously tho... if its a no no to drain in to the combined system (can any one say why for clarity in my mind?)
as the house is in the middle of the plot can I run the land drain round the ends of the house and into the lower acres? Its sandier soil there, my guess is the cut into the slope a dumped the spoil on the back hence more clay on that side of the house.
Would it just soak away or would I need to build a "SUDS" - if so how big?
thanks for all the help so far
Posted: Thu Sep 16, 2010 5:36 pm
by lutonlagerlout
i kept quiet on this tim
but no one seems to have ppointed you in the right direction yet
install a linear drain where the water collects and take the outfall pipe from this to a soakaway of suds system at the front of the house
via 110mm underground pipe
if you want to harvest rainwater maybe get some water butts,before you invest in tanks etc
IIRC correctly my neighbour used rainwater for washing their hair when i was a kid as it was softer and lathered up better
LLL
Posted: Thu Sep 16, 2010 9:53 pm
by seanandruby
.......i thought giles answered the question and gave sound advice. ???
Posted: Thu Sep 16, 2010 10:19 pm
by Pablo
lutonlagerlout wrote:i kept quiet on this tim
but no one seems to have ppointed you in the right direction yet
install a linear drain where the water collects and take the outfall pipe from this to a soakaway of suds system at the front of the house
via 110mm underground pipe
if you want to harvest rainwater maybe get some water butts,before you invest in tanks etc
IIRC correctly my neighbour used rainwater for washing their hair when i was a kid as it was softer and lathered up better
LLL
It's groundwater not surface water LLL so a channel couldn't work. In certain circumstances you can use the main if there are no other options but you need to seek permission. This would be along the lines of a soakaway being unfeasable and you are unable to use all the collected water within the property before the tank overflows. You can't water the plants in the winter and the only internal use is the toilets so you will always have a surplus if you have no soakaway so the only option is to pump it or outflow it to the main. My guess is that being on a slope you have a spring or are close to the water table so a soakaway won't work. If you have room could you intercept the water at the top of your property with a drain that then outflows at the bottom.
Tank wise you would need to seek advise from a drainage contractor who will assess your roof size average rainfall groundwater etc which will determine the size and system you'll need and what it'll cost.
Edited By Pablo on 1284672074