Connecting rainwater downpipe to an inspection chamber

For several reasons, the only way to deal with my blocked soakaway is to sneakily connect the rainwater downpipe into an adjacent inspection chamber.

Three questions:

1 - The chamber is rectangular concrete and I will come through one wall, above the invert, how do I seal the entry? This pic shows the chamber
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I'll be coming through at the top left. (The flow is up the photo)

2 - If I just end the pipe after it has entered the chamber it will dump against the flow, so I plan to have an elbow inside the chamber so the rainwater drops vertically on to the invert - are there any alternatives? (I can't get through the other sides without several bends)

3 - What's the name for the type of trap that a downpipe goes into (the type without a hopper)?

Thanks.

Reply to
no_spam
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The Conservatory builders piped the rain water into a similar inspection ch amber albeit brick lined and deeper. The pipe just comes in below the concr ete surround that holds the lid and just pours into the chamber. I do not t hink it will matter going against the flow as it will simply drain out whic h ever way the flow goes.

Richard

Reply to
Tricky Dicky

Did they do anything special to seal the pipe, or just regular mortar?

Reply to
no_spam

I think I've found an answer to Q3:

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with either a debris gully
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or a rainwater adapter
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Another question: I will need a very short (less than 1m) run of 110 straight pipe - are there any problems with using grey (which I've got in the "useful bits" store?) underground?

Reply to
no_spam

The pipe is only sealed with mortar. As yours is a pre- cast concrete liner you will probably be best served hiring a diamond core drill to make an op ening for the pipe. As for grey pipe or terracotta I do not know if it make s a difference only that terracotta is easier to spot during excavation and it matches traditional clay pipes.

Richard

Reply to
Tricky Dicky

Thanks, but I'll probably stitch-drill it.

Reply to
no_spam

You need permission of your sewage company. That will depend if the local sewers have the capacity to deal with rain water without flooding sewage out.

It needs to enter the chamber like the joining pipe does.

It's a sewer - it needs a trap/hopper to seal against air flow, or it will smell.

Reply to
Andrew Gabriel

It may vary with different companies, but if this is the first time rainwater will enter the sewer rather than through a soakaway you'll be charged by the sewer company as they have to treat the extra water.

Reply to
Jeff Layman

it got noticed in our village recently when the extra water wouldn't all fit into the sewage pipe after heavy rain, so it backed up and left raw sewage over people's lawns.

Don't do it.

Reply to
charles

I agree that it should, but I need to work in the world of the reasonable and possible. In this particular case, because of the proximity of the house, other walls and a vast TPO'd tree, achieving the ideal would be impossible without an unreasonable (for rainwater) amount of work.

I'm not stupid enough to forget a trap, but a hopper is not needed if there's no need to collect surface water.

Reply to
no_spam

That chamber looks like a foul drain to me. Do you have separate systems for collecting foul water and surface water? If so, it may well be illegal to feed rainwater into it. Check with your Building Inspector. Unless you do it secretly, you'll need to have your connection inspected, anyway.

I got away with putting roof water from a conservatory - along with grey water from a new utility room - into a foul drain about 25 years ago because most conservatories were not subject to Building Regs at the time. The inspector said: "Since there are no regs, I can't tell you what to do with the water". I'm sure it would be different today!

I think you asked later about using grey/pipe underground. AIUI, that's ok. You *can't* use terracotta coloured plastic above ground because it's not UV-proof. But I think grey/black pipe is ok above *or* below.

Reply to
Roger Mills

Lots of people are historically charged, even if they aren't doing it.

A friend did this ~10 years ago. There wasn't any extra charge, but they did need to know the horizontal surface area draining into it, and the permission granted is lodged with the local authority building regs based on that surface area.

Some (different) friends in East Finchley moved in just after Thames Water had inspected the whole road to make sure everyone's surface and waste water was going to the right places. Lot's of the houses had to get plumbers around reroute their waste pipes to the right places, which fortunately had been completed just before the friends bought their house.

Thames Water inspect whole areas when they find the sewer flow increases more during rain that it should, or soap suds/sewage start appearing in surface water drains.

Reply to
Andrew Gabriel

Thanks, I knew that the grey is UV stabilised for use in direct sunlight and I could see no reason why it couldn't be used underground.

For the naysayers: the gutter serves a large roof area and there are three downpipes; I've already rebuilt two of the soakaways but this wasn't possible for the third without destroying a large part of the root system of a 200'ish year old tree. The job is now done. I dug down the side of the chamber, chalked the appropriate hole near the top, put a board inside the chamber to catch the debris, stitch-drilled the hole and then used the SDS chisel to break-out and tidy-up. The pipe only needed to be about half a metre long and is now mortared-in place, with a spigot bend to turn the flow somewhere close to the right direction. The digging is back-filled and the relevant guttering has all been re-done to move the outlet to the right place. All in all a good days work. One small co*k-up: I forgot there are different sizes of downpipe and got an adapter for 80mm rather than 68 - only realising when I'd fitted it.

Reply to
no_spam

No-one questioned the physical possibility of what you wanted to do. Whether it's *legal* is an entirely different matter!

Reply to
Roger Mills

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