Kitchen Waste Problem

[CadXS]

Here is a picture of the kitchen waste on my new house:

The white pipe with the dog leg is my kitchen waste. The straight white pipe is my neighbors kitchen waste and the small bottom pipe I think is lead and probably my old kitchen waste not in use.
They are join into the grey soil pipe running horizontally across the front of my house which has a rubber coupler on the end connecting to a clay 90deg bend through the wall.
The other side of the wall is this:

The wastes exit into this gulley with a little cracked conrete channel to feed the water from the clay pipe elbow into the drain.
I am looking to replace soil pipe with normal 40mm waste pipe and change the grating cover on the gully to one with a waste pipe inlet to neated this all up.
I have a couple of questions. I don't want to cause hassle with my neighbour about their kitchen waste draining into my waste pipes even though I'm sure it shouldn't. Is it a problem to have the waste from 2 kitchens going into the same waste pipe and could it cause issues if say 2 washing machines are emptying at the same time? Also do you think there is enough drop on the waste if it starts where it exits my neighbours kitchen (the middle pipe). I was thinking to drop my waste pipe vertically down into a T to meet this pipe.
Thanks

 

[RandomGrinch]

I am no expert, so please feel free to ignore me! I think the length of the pipe run and the multiple inlets may have been why 110mm pipe was used.
I believe a run of over 4m requires a 50mm pipe?
This post might be useful:
https://www.diynot.com/diy/threads/waste-pipe-run-diameter-and-length.469308/

 

[CadXS]

Thanks for the reply. I agree with you as to why they have probably done it, I just think it looks pretty horrendous. It's also falling off the wall.
I think 50mm pipe allows a run up to 4m unless you fit an AAV then I think it can be longer.
I am thinking of going to 50mm where the pipes exit the respective kitchens, fitting an AAV and I hope the fall will be enough to clear the pipe. If it was just my waste, which is higher, they would be no problem, but I have to incorporate my neighbors waste as well which exits lower on the wall.

 

[thomp1983]

Depending on the depth of that drain with a bit of work you could probably get that pipe either in the ground or right at the bottom of the wall and still maintain the correct fall and then you could just run both wastes vertically down the wall.

 

[RandomGrinch]

Depending on the depth of that drain with a bit of work you could probably get that pipe either in the ground or right at the bottom of the wall and still maintain the correct fall and then you could just run both wastes vertically down the wall.

Does the drainpipe go to a soakaway, or do they end up in the same drain?

 

[CadXS]

Depending on the depth of that drain with a bit of work you could probably get that pipe either in the ground or right at the bottom of the wall and still maintain the correct fall and then you could just run both wastes vertically down the wall.

I know what you saying but what is hard to see from the pictures is that the house sits on the edge of a mill stream with little to no banking between the house and stream. Dropping the horizontal 110mm pipe to the bottom of the wall and burying the pipe would be virtually impossible without some kind of underpinning work on the bank. I see what you mean though about running along the bottom of the wall but I think it would make the pipe too low, actually below the level of the sewer that crosses over the stream in a steel pipe. I will take a picture in the morning to try to explain. The horizontal 110mm pipe is actually about floor level on the house even though it looks a metre plus up the wall.

 

[CadXS]

Does the drainpipe go to a soakaway, or do they end up in the same drain?

Not 100% sure what you mean sorry. The 110mm with the kitchen waste water goes into the gully shown in the second picture, which then connects to the main soil pipe somewhere underground. This then feeds to an inspection chamber at the side of the stream and then over the stream in a steel pipe and I presume into the main sewer running down the street.

 

[RandomGrinch]

Not 100% sure what you mean sorry. The 110mm with the kitchen waste water goes into the gully shown in the second picture, which then connects to the main soil pipe somewhere underground. This then feeds to an inspection chamber at the side of the stream and then over the stream in a steel pipe and I presume into the main sewer running down the street.

Sorry, I didn't realise there was a stream there. My drainpipes end up running to the same inspection chamber as my soil pipes, so I wondered if your drainpipes entered the same gulley, but lower down - I know that's not the case now!
...and silly question! Have you checked to see if the neighbours pipe is still in use? They also may be willing to contribute to the cost of a solution (Pppfff!)