underground rainwater pipes falloff slope

[biggerlebowski]

hi there

I've just had my plastic underground pipes dug up for about the fourth time due to leaks.

The builder fastidiously replaced all the couplers and put the pipework back. Then assured me the trench was ready to backfill with shingle and topsoil. So I ordered and infilled a ton of shingle, then finished with topsoil. It was a muddy backbreaking job, since the soil contained hardcore which I carefully removed by hand with a rake.

I then decided to check the falloff angle on the last remaining bit near the house and found, to my horror, the pipe is going uphill. I have to tilt the 18 inch spirit level an inch to get a moderate fall.

I've read that sewer pipes need a 1:40 fall, but is it the same for underground rainwater pipes?

I can't quite believe I've got to dig it all up again. I suppose the only blessing is it's surrounded by pea gravel so I'll avoid trashing the couplers with the digger.

Best
Tom

 

[Nige F]

hi there

I've read that sewer pipes need a 1:40 fall, but is it the same for underground rainwater pipes?


Tom

No it`s not - so you could leave it - but I`d put an accesible ( bottle gulley ) @ the bottom of the rainwater downpipe , so if there is any silt you can shift it That would be a good idea even if the pipes had a fall . So you get over a c*ck up and end up with a better job anyway