Very bad smell - from gutter drain pipe linked to sewer

[Shane M]

Hi, a sceptic tank has been installed in the estate up the road. We keep getting very very bad sewer smell at certain times of the day. It has been confirmed that this is when the tank is being emptied. My house is old and previous owner in their wisdom ran one of the 3" cast iron rain water down pipes directly into the sewer without a trap. We suspect this where the smell is coming from. I have thought about installing a rat trap (flap) valve where clay pipe comes out under inspection cover-but end of pipe is complex shape so could only fit inside and have not been able to find one. No possibility of fitting conventional trap or drain because bottom of vertical cast iron pipe is embedded in stone arch. So looking for a device that can be fitted into vertical cast iron pipe possibly or any bright ideas? Willing to make or adapt something if anyone has any experience. Help would be much appreciated. It is a very bad smell!

 

[Ric2013]

The best thing would be to dig a soakaway 5 metres any building and dig into the surface water drain under ground and relocate the outfall from your gutter to this. If possible. Then you can cap off your existing run where it joins the foul (better not to leave dead legs in sewers as nice place for rats to nest.

This would be notifiable work under the building regulations, though I dare say many wouldn't notify.

If you really want a short term bodge, could you somehow mastic a 40mm HepvO valve into the top of the drainpipe? But I would only suggest this if you aren't anticipating massive amounts of water, which a 3" pipe would seem to suggest the possibility there may be... And I wonder if the drainpipe is in full sun and how well the rubber membrane in the HepvO would cope.

Can you not cut a section out of a length of the clay drain and use a universal rubber transition coupling thing (the rubber ones with the big jubilee clips) to transition to something with a more normal shape that would work for your rat trap? I'd be inclined to stick a rodding eye or two close to it though, just in case, as I understand your rat trap is designed for the outlet close to an inspection chamber, so still a bit of a bodge.

I have successfully cut Supersleve clay pipes with a diamond masonry cutter in an angle grinder. I expect they'd work on salt glazed pipes.

Any good?