Kitchen Sink Drainage Problems

scaredofdebt

Not really sure where to start with this, the whole story!

We had an extension built in 2021, this involved moving the kitchen sink into the new extension and removing the old one.  The new sink is about 10 feet from the old sink.  I'd just assumed they would plumb the new sink into the old drain as it was fairly close, the old sink drained outside and then into the main drain for the house into the sewer in the street.

Fast forward to now and the sink is blocked, Dyno Rod came out today and couldn't unblock it, the chap reckons the sink isn't going into the main drain.

Now, we had an ASHP fitted around the same time as the extension was built and one possibility is that when they installed the fan, they drilled through the pipe that goes from the sink to the outside drain and that has over time gradually blocked up.

However, he also put a long snake into the drain and despite it going 10 meters or so I couldn't hear it when I was stood outside next to the fan for the ASHP, so he is wondering if the plumber has simply plumbed the drain from the sink into any old drain maybe a soakaway.

He recommended getting a builder out who specialises in drainage to have a look.

Any advice welcome.  The builders went bust just before they finished our extension and we don't have contact details for the plumber or anyone involved with it.

I don't really want to rip up the kitchen floor and concrete if it can be avoided.

teaselMay

A lot of water must have gone down that sink drain in 4 years, it must be going into a drain of some description or else you'd have had a problem much sooner. Are all the other drains working properly?

scaredofdebt

Yes, all other drains, sinks, toilets no problem.

doningtonphil

We weren't sure of the routing of our drains. We also had a couple of blockages, each time cleared by the water company even though they weren't obliged/supposed to.

Anyway, for eace if mind we got a CCTV survey done. They send a camera along the drains abd measure each location (bend,inlet,defect etc). They then send you the electronic file. 

About £150, but money will spent

ThisIsWeird

I'm sure you've considered this, but is there an alternative route the waste pipe could take? Eg, follow the original route?
Any plumbers suggested this?
Could you post the plan of your extension, to show the sink and underground waste positions?

scaredofdebt

ThisIsWeird said:

I'm sure you've considered this, but is there an alternative route the waste pipe could take? Eg, follow the original route?
Any plumbers suggested this?
Could you post the plan of your extension, to show the sink and underground waste positions?

It is either a new pipe into the drain that runs down the side of the house or it does use the old kitchen sink drain, I've just put some food dye into the sink and will have a look to see if I can see that in the main drain.

scaredofdebt

So, after a lot of digging, literally it looks like they didn't connect the waste pipe from the sink into the main drain, so we have 4 years worth of waste water under the house, or in the soakaway etc.  We've had some builders digging around the outside of the house and they have struck water, plus the old pipe which isn't connected to anything, but no pipe coming out of the house.

We now need a new drain putting in, going to be rather disruptive, new floor needed etc, any advice on what is easiest?

Also is this water going to be causing a problem for the foundations etc?  Should we pump it out or leave it?  House seems fine, no cracks in the walls or anything like that.

There is a pipe from the sink under the floor that goes pretty much up to the external wall as I saw them laying it, it just doesn't go through the wall by the look of it, so do we use that or just put an entirely new pipe in?

Any advice welcome.