Domestic Sewers

[GreenDog]

I've just been replacing the cover and frame for an access chamber at the back of the house and have ended up scooping out a load of muck and stones from the bottom as there was about 10cm of standing water down there (yes I've washed my hands before logging on )

There are 2 outlets from the chamber, 1 almost level with the bottom and one that seems to be attached but is a little higher up. The lower one is blocked with god knows what but the top one flows OK. Does it matter as long as waste can escape or should I be getting some draining rods out ?

[Engineer1]

Personally i'd rod it as unless you know what the blocked pipe serves it could get messy.

[mycroft]

Hi greendog . I suspect what you have is a gully , its like a toilet bend or trap in your manhole . Just above the trap is an access plug and its common to find they have been removed so the waste just flows past the trap . This means solids will build up in the bottom of the drain . If this is the case you will not be able to rod the drain cos you will hit the back of the trap . If you want to clean it so it works correctly you need to prod around in the the bottom of the trap to clean out any build up, you might find a bit of debris that has caused a previous blockage , if you have a pressure washer it will help . I have found in the past filling a large bucket or bin then tipping it down the manhole often flushes all the rubbish through once you have cleared most of the blockage . Its a messy job but sadly rewarding when you get it working properly .
Or you could just leave it how it is .

[GreenDog]

Cheers the ubend theory looks likely. I'll have a go at clearing it again

[Stegel]

Sounds like your house is pre WWII or thereabouts - more modern drains pass straight through the inspection chamber, whereas previously designers had a thing about sewer gasses and put a trapped U-bend at the end of the run. As already said, there is a higher level by-pass with a cover that allows rodding downstream which otherwise would not be possible because of the U bend. Suggest you scoop out all the muck from the U bend to allow the drain to run properly - you may even find the lid to the by-pass is causing the blockage in the U bend.

[GreenDog]

Should be getting some rods tonight so hopefully it'll all be flowing freely again soon.