combined sewer and roof drainage

Just had a moment of drama. The main roof gutters of me and neighbour had a shared downpipe that I guess was supposed to split equally between the 2 properties. I had temporarily routed both roofs onto neighbours side whilst extension work is in progress (a bit naughty I guess). Anyway, just had downpour, and she phones saying it overflowed and flooded her back door. Now, we have combined sewer and drains here (1930s house). I have temporarily re-jigged it so that all water goes to our side, and down our soil pipe, which currently only extends 2 feet above first floor, awaiting the extension roof. This will certainly keep her happy. But it got me wondering. For a combined sewer, why not just put the roof drainage into the top of the soil pipe, which passes right by the gutter ? I mean, a 4 inch pipe from the roof must be the best solution. Even in heavy rain, there would never be enough water from the roof to prevent venting when the toilet is flushed. ?? Simon.

Reply to
sm_jamieson
Loading thread data ...

When the soil pipe gets blocked... and it rains... ... I do not think your toilet bowel will handle the volume...

Reply to
js.b1

Good point. But equally all that water may stop it getting blocked ! And if the blockage is downstream enough, this will still be a problem. Simon.

Reply to
Simon

I don't think anybody's bowels would handle the problem...

Reply to
Bob Eager

When the soil pipe gets blocked... and it rains... ... I do not think your toilet bowel will handle the volume...

Classic!

Reply to
Graham.

Because the top (IE the open end of the soil pipe) has to be a minimum of one metre higher than the highest opening window, and in your scenario, it would be gutter height. This is why soil pipes have the swan neck to take them past the eaves and gutter and upwards for a stretch before venting.

Reply to
Phil L

Well why not have a side inlet boss into the soil pipe ? Its not so different from an entire large bathtub emptying into the soil pipe through an identical inlet at full force a few metres below. Simon.

Reply to
Simon

Except that a bath or basin has a trap to prevent sewer smells getting into the room - doing it the way you describe would still vent sewer gas at the gutter height, IE about a foot, or even less, above an opening light.

Reply to
Phil L

depends if you were sat on the throne when the pipe blocked during a downpour i guess.

Reply to
gazz

Rainwater into the sewage system isn't great from the point of view of the water company. Older properties would discharge rainwater to the sewers, but post 1950's built houses should drain gutters to a soakaway. If you had any sort of extension build, then BC would insist on soakaways.

Why don't you divert the rain into a large tank and use it for flushing loo/watering. As a plus point if you are on water meter then you won't pay to flush/ dispose of your Richard III's.

Dave.

Reply to
Dave Starling

Soakaways aren't permitted within 5m of a building, and they have never been insisted upon by anyone at any time, least of all BC. You are thinking of a dual system, and the rainwater doesn't go to a soakaway, it goes to a stream, river, ditch or similar, to save unnecesary treatment of what is basically fresh water

He might save a bit of metered water, but he'll still have to pay up for the turd treatment

Reply to
Phil L

The sewerage treatment charge round here is based on the metered input so he would not be charged for rainwater source flushed materials

Reply to
cynic

BCO was OK with new roof draining into sewer. I think because we are on clay, soakaways dont really work. Simon.

Reply to
Simon

Yeah, I guess you could put a trap in ! Anyway I have trapped gully to drain into on the plans, this is just interim ;-) Simon.

Reply to
Simon

In recent years they don't even bother about dual systems. Several times we have uncovered them and asked whether we have to run the rainwater gullies into them and each time the BCO has stated that he couldn't care less

Reply to
Phil L

Interim is fine, but as you said, the gullies have a trap in them and this is the reason why

Reply to
Phil L

I had always understood that it was considered impossible to polish them? Is this another job where the angle-grinder comes out?

Reply to
Steve Walker

On Sun, 28 Jun 2009 21:02:38 GMT, a certain chimpanzee, "Phil L" randomly hit a keyboard and produced:

Since (IIRC) 2003, there is an order of preference for disposal of surface water that starts with disposal into a soakaway. Where that isn't practical (such as a site with not enough room to have a soakaway more than 5m from a building), then the next option is a watercourse. Where that isn't an option, it can then discharge into a sewer.

A soakaway is always preferable to a watercourse, as it smooths out the flow from sudden downpours.

Reply to
Hugo Nebula

Hugo Nebula wibbled:

I'd like to convert from sewer drainage to soakaways in due course fo rthe rainwater.

Is there a solution to 12" soil on clay? I was considering running perforate pipe over as much distance as possible (say 4-5m) ( and >5m from the house) about 6" down under the lawn.

Or is this likely to just give me a hideous bog?

Cheers

Tim

Reply to
Tim S

Probably.

For no reason that I can fathom, pissing around with water has become a bit of a project here, and its curious as to how it behaves.

I mean, I get surface water over the clay slope, yet the pond - unlined

- always stays a foot to 18 inches below local ground level..although I have to admit, that's about the same garden level where the water starts appearing at the surface..

I have come to the conclusion that the clay - certainly in winter, is pretty much impervious, and its really a matter of getting the water off it and into the nearest ditch as painlessly as possible.

I.e. a soakaway as such is likely to be full most of the time, and is not ideal. If I went deep - very deep - there's eventually chalk, but that IS a long way and impractical.

So the only recourse is to buffer slightly, and try and eliminate surface puddles. Now I do that with the pond itself, which is about te same as a large soakaway really and is fed from guttering and french drains round the house. This keeps the upper garden dry enough, but the water ends up in the lower garden and here the thing that works locally, is to build up the surface with limestone or gravel, and soil over. The water still runs, but its slightly under the surface.

As far as perf pipe goes, use that to DRAIN an area, not to transport to a soakaway or ditch..

Use plain old pipe for that.,

But overall, look at your land in topological context: at some point the water has to percolate down to an aquifer type structure - chalk/limestione - or end up in a ditch, stream or river.

Soakaways are really only buffers, there to take the peaks and reduce it to what the percolation level can handle. And on clay its sod all. At least once the rain has been steady for a few days and its saturated ;-)

So if you can couple into some local drainage system, by all means build a soakaway, but make sure than downhill of it you have a pipe that can take the water away when its 'full' to a ditch or similar. Or someone else's land ;-)

I.e. You've done your civic buffering duties, now its Someone Else's Problem ;-)

Reply to
The Natural Philosopher

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.