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Posted: Thu Jul 26, 2007 10:33 am
by daveross
I have a combined waste system in need of repair and improvement. Firstly the garden slopes toward the house but the drainage system slopes away from the house to the sewer, meaning I am very limited as to the depth of pipes at the house end. Also the yard level is higher than the DPC but cannot be lowered since I can't sink the pipes any lower. I was thinking of solving this by running linear drainage around the perimiter of the house at a lower level than the rest of the yard. Will this work? Can I connect my gutter downpipes and washing machine waste into the linear channels which will connect into existing drains? The yard is approx 15msq and will be dug up and resurfaced. Will a combined system cope with waste water, gutter downpipes and surface water in these circumstances? We've had flooding, but currently there are cracked pipes, a downpipe discharging directly onto the yard and occasional blockages due to buliding work. Phew! Thanks for the excellent site.
Posted: Thu Jul 26, 2007 6:10 pm
by lutonlagerlout
it really really is a bad idea mixing rain water and foul,even if it is only (washing machine water = full of hair and detergent to block up the drains)
the current thinking is that even rainwater pipes should have a back inlet gully before going to the RW system to stop the pipe silting up
your washing machine water should go to the FW sytem
there are various workarounds noted here
a photo speaks a thousand words
regards LLL
Posted: Thu Jul 26, 2007 7:40 pm
by daveross
Thanks for that, very useful link. I thought combined systems were considered OK?? I could try and seperate the foul and surface water up to the inspection chamber, which is about half way between the house and the sewer. From there they would mix in a single pipe. Would this help?
Posted: Thu Jul 26, 2007 8:55 pm
by lutonlagerlout
in my part of the country (beds) its a hanging offence putting rainwater into the sewers,and as for putting sewerage into the rainwater pipe .................
cheers LLL
Posted: Thu Jul 26, 2007 9:17 pm
by Dave_L
In my 1960's property we have seperate foul and surface water drainage systems, but upon lifting some of the large sewer covers out in my back lane, they both flow into the main sewer...........odd 
Posted: Fri Jul 27, 2007 8:14 am
by daveross
But if a soakaway is not possible, where else is the rainwater supposed to go?
Posted: Fri Jul 27, 2007 3:44 pm
by lutonlagerlout
soakaways are nearly always possible ,they can just get expensive and impracticable
LLL
Posted: Fri Jul 27, 2007 8:53 pm
by matt h
if your yard is already over dpc,hope you are lowering it anyway, or you'll be experiencing severe rising damp!:(
Posted: Sat Jul 28, 2007 9:38 pm
by Mikey_C
You need to study Part H of the building regs, the fact you already have a combined system implies it is alright to do so, my is combined because I am within 1/2 mile of the cliff top (having soakaways causes cliff errosion according to the drainage comapany that came round to "repair" mine before I did my drive). If a soakaway starts get to expensive you could always price up installing a rainwater harvesting system, which uses a large tank to store filtered rainwater, which the house then uses for flushing toilets, washing cars and watering the garden, it will make the soakaway look cheap!! 
Best of luck.
Posted: Tue Jul 31, 2007 7:45 pm
by daveross
Thanks for your help. The area where the yard is high is tanked as a temporary solution, but it will be lowered. It's clay soil here so I'm not sure about a soakawy, though my dad, up the road insists he has a pit filled with gravel which has worked fine for 20 years! I'm going to get someone to come and have a look. Thanks again.
Posted: Tue Jul 31, 2007 7:58 pm
by Ted
Mikey_C wrote:You need to study Part H of the building regs, the fact you already have a combined system implies it is alright to do so, my is combined because I am within 1/2 mile of the cliff top (having soakaways causes cliff errosion according to the drainage comapany that came round to "repair" mine before I did my drive). If a soakaway starts get to expensive you could always price up installing a rainwater harvesting system, which uses a large tank to store filtered rainwater, which the house then uses for flushing toilets, washing cars and watering the garden, it will make the soakaway look cheap!!
My harvesting system only stores 1600 litres. It filled up very quickly this summer.
It overflows into the sewerage system when full...