Backflow of sewage into gutter trap - any ideas?

[chelly78]

Can someone explain what is happening.

I have had a new soil stack put in as house did not have one when we bought it (had been removed and macerator fitted) which has resulted in some changes to the drains. The soil stack goes straight into the foul drain which has an inspection chamber outside. On lifting this there are 2 points of entry running into the drain - one is the soil stack, the other is water from the kitchen sink and washing machine which is completely seperate. Water from the gutters also goes into this drain and I assume that the gutter connects to the soil stack as when you pour water down the gutter drain it comes out the same pipe as the soil stack. Cannot see how it connects as it is all encased in concrete

The problem is that recently i have noticed toilet paper and waste collecting in the trap where the gutter drains. If i get a hose and stick it into the gutter trap then it will clear but surely this shouldn't be happening. What do you think is the cause and what can i do about it? With the recent hot weather I don't really want raw sewage collecting in the gutter trap.

Thanks

 

[chelly78]

Untitled

• chelly78
• 12 May 2008
• 1

In case i am making no sense. Drain on the left where the gutter goes is a trap i think as should just have water in it but is filling with waste.

I would be grateful for any suggestions

Thanks

 

[JohnD]

take the lid off and empty the bath or sink.

I have a feeling there is a blockage, as the level in the chamber should not rise much.

either the blockage is partial, or the pipes are cracked, since the level seems (eventually) to go down.

I think drain-rods are required.

Try to find evidence that the drain you have used really was constructed as a foul drain and not a rainwater drain.

The problem might be on your land or further away.

Try to find the next inspection cover in the row and look down that. If you have a terraced house it may be in next door's garden, or it may only be in a few of the houses.

If the drains come from several houses before going out to the street, it may be a common sewer in which case you may be able to get the council to unblock it for you (but if it needs repairing, that's down to you, so start looking at your house "deeds" to see what they say about responsibilities for cost sharing)

If your house was built before 1945 or is on clay, there is quite a good chance that some of the old salt-glazed pipes or their traps will be broken.

 

[chelly78]

Ok, drain was filled with waste +water again today (probably about 10cm deep) so cleared it with a hose then filled up bath and kitchen sink with water and took lid of inspection chamber. Emptying sink made no difference to the gutter trap as they are completely seperate.

On emptying the bath the level of water in the gutter trap went up and down 1-2 cm repeatedly as the water came down the soil pipe. Although there was constant flow of water from the bath the rate seemed to be variable. Does this indicate anything? - the soil pipe is pretty long as the bathroom is in the middle of the house.

I assume that the gutter drain must have something a bit like an s bend in it to keep water in it as a trap (to stop smells coming up from the foul drain) but as water comes down the soil pipe some of the waste and toilet paper gets carrried into the gutter drain and then can't get back out again unless i clear it myself. The pipes are all new so hopefully not cracked

Is there anything that can be done to stop the waste going into this or am i just going to have to keep clearing it myself because that is how it is designed.

Thanks

 

[JohnD]

sounds like the piping is wrong, but it's beyond me now. possibly you could prod up the pipes and see if you can puzzle out the route and any signs of blockage.

A pity that new concrete has been cast round the pit to make it more difficult to get at.