Neighbour extension and drains - advice?

[MrsSmith123]

Terraced house. Neighbour is planning extension on back of the house over patio.
Drain set up is that their drains all run through our property to get to the mains. There's an access point on patio across the boundary where their drain meets ours. It has always been assumed that responsibility for maintenance is mutual.
They want to extend to the rear past the point of the drain access point, and build their extension around the access point so that they don't have to make any modifications to their drains or ours.
This will mean that in future the drain could only be accessed from our property. If it blocks and floods we will be more impacted than they are, and that they could block it from their side but we would be left having to sort and pay for unblocking. It would also mean that they might need access to our property to unblock drains on their side.
Another concern is that we won't be able to do a similar extension in the future as once they've built over their patio it will be impossible to move the drains further away from the house.
Of course we'd rather that they move the access point further away from the house so that it remains mutually accessible.
Is there a process for this? Our surveyor says that it isn't covered by the party wall agreement.
Neighbour not interested in dialogue or good relations.

I don't think you will pay for unblocking if the blockage is their side, although the access could be an issue?

Are they needing planning permission? I would ask a solicitor about the party wall rights.

Www.water.org.uk gives good advice. Plus ask your water.sewerage company. Eg Thames Water etc. This may well be an issue as the pipes serve more than one property. I would see if someone will come out an evaluate the issue. The pipes can easily be moved to the exterior of their extension. You also need to be aware of where the pipes are that belong to the water company because there are rules about building near them too. Hope you get it sorted.

One other thought: could you have your own pipes routed through your own land to avoid sharing? Something to ask about maybe?

Thanks for suggestions.
It seems that neither planning permission nor party wall touch on drains. That's what we've been told anyway.
We'll look at the water company and see what they say.

The building warrant will cover drains. Speak to you council planning office.

Great. Thanks Umbrella

Look at the Thames Water information on "build over agreements". They say a drain can run under a few houses before an access point. So you might be able to still do your extension with shared drain effectively being landlocked.

However the sensible thing surely is to talk to your neighbours about your future plans - and jointly pay to move the manhole.

Building warrant/Building Control have nothing to do with Planning so don’t ask them about the drains, which you have already discovered further up.

Is your neighbour the head of the connection or do you know if the drains also run through their property from the other side? If it’s the latter, it’s a public sewer and would require a Build Over Agreement from the respected water company. The water company will have advice and guidance as to what can be built over, clearance around the sewer and access points. If it’s a private sewer (on their side), they can do pretty much what they like with it.

Contact your water company after reading their guidance on building over drains and pipes.

Building control will look at the drains on behalf of the water authority so , they should see that on the drawings that are sent to them. I think you will be able to extend though you might have to move the drains.

The Water Authorities employ their own staff and have their own rules. Building regs are the neighbours business. It’s their extension.

Yes what I meant was BC will oversee the works done around drain issues on behalf of the water authority. Unless it was a huge sewer the WA won't send someone out .

Interesting. It must be private.
We'd happily pay for rerouting our drains if we wanted to extend, but if they've already built over theirs it will be too late - we'll be stuck.
No point in discussing with them - they want it cheap and now, which is why I'm trying to find out if we have any rights over this to stop us being 'boxed in' by their choices.

What will they do then if you say you intend to build an extension as well ?

If it is Thames Water, the drains that run in the gardens of houses as a shared utility may have been adopted, even if they were originally private. Thames Water have not mapped all the drainage, but are updating as they get applications to build.
Before you can build, you would need a build-over agreement from the water company and so would your neighbour

Having done an extension where we built over an existing drain excess point we were required to by Thames water to build a new excess point at the front of the house. We were lucky the drain ran through the property so we could do this.

I would definitely raise your concerns with your local water board highlighting that your neighbours won’t be able to access their drain access point if their are any issues.

They need specific build over permission and this needs to be inspected by water company.

They may need permission from the water provider to make changes. Cost a couple of hundred. Then a survey of the drains after completion to ensure the water flows correctly. Once happy the water company will notify building control all is well. We moved ours and did not need to notify the neighbours except when the flow was off out of courtesy. Had no effect on access or change of any responsibilities. They send down cameras on mini carts/ technical term? to see where any blockage is.

Hi guys new here and not sure if anyone will see this but found this and am in similar boat- live in a 1930’s terraced house with shared waste drain in back garden. Neighbour built their rear extension in 1960’s and built right upto the drain she has all her waste pipes coming out side and into that drain. I have also extension but it appears my previous owner left room to be able to acces the drain however my neighbour did not and has to come into my property to acces her pipes and the drain. She has placed her fencing within my boundary about (20cm) so she gets the full width of her garden - she was meant to place it on line of where extension ends and placed infront of her facing wall. Getting a boundary surveyor is costly and they will just says it been lik th is over 10 years
She’s created a sort of door attached from edge of extension end to the fence which she open to come into mine -
We’re not on friendly terms and recently she got a shower vent that a builder came in my garden property to allow access to fit it. It didn’t take long but the audacity - I read that you have to allow access to neighbours for repair etc her property . I didnt say anything as I don’t want to bring something up now when I can’t afford to start work it’s my future plan. So I didn’t want to cause more problems (we have already had dispute about front boundary she wanted to take some of my land) when I’ve actually not started work it’s something I’m thinking for future but im worried that if she carries on doing what she wants expecting to be access from my side it may cause me problems for doing what I want.

I am thinking of building to full width of my rear extension so possibly like hers upto the drain (will apply for a build over) and I can redirect my pipes if needed ( so it won’t be shared and will just be hers ) however my worry is , that me building within my boundary and the full width of my boundary , it will not allow her acces to repair pipes (will have a 20cm gap) or even the water company to come out , could this be a reason I could be denied to build my full width?- she also has already a small window which get no light or air tbh but it’s there (I read somewhere that neighbours shouldn’t have windows on sides facing neighbouring walls etc and have it so they can access it ) also this may cause a problem for me as I’ve read building control can deny it saying its blocking her light etc - which is bull really. And I hate that neighbour needs to agree - she doesn’t ask me permission for anything and she’s done all her stuff long ago- I’ve had a look around on internet some say do what you want within your boundary as in truth it’s not my problem she didn’t leave room on her sides to allow access thinking she will just come over to my land to access her pipes or maintain the vent or Whatever.
ive been told I should just fence that gap. that way she won’t come into my land . but the drain gets blocked regularly and because it’s open on my side I sort it out and have to deal with the awful smell - that tiny window she has is high up and smell doesn’t reach her but I have a window directly above the drain so it’s awful.

sorry it’s a long one- also I called Thames water and a few things they said they don’t have any drain plans for my property and if it’s blocked they can come over to look and also I told them about neighbour built upto drain they said they can check if a build over agreement was taken and if not neighboir will need to rectify with the gap etc and take it further - but I know if it applies as it was done in the 60’s and it didn’t apply then?

but my concern is she will just turn around and say well water company can access through my side is open
if I complain to the water company (which I’ve been told I can) they will come have a look and write to her to fix the problem if no build over agreement is there - I doubts she’s going to break up her extension to now create a gap for access from her side which tbh she will just say to f* off

but my thought was she can fight with the water company- I was happy to know thats the solution when it comes my time to do it. however on further research I read something about she can get an indemnity as it’s so old and it didn’t apply then so she gets away with it. Her pipes come out the sides but the drain is up against my wall close to my front facing wall on rear and is causing water damage but I don’t know how to get her to move her pipes ? As her bathroom is on that side ?
My hope was of the water company say she has to leave room and create that to access she has no choice but my fear is as long as my side is open she will use that as a opportunity and say neighbour has to allow access(I read somewhere) also if I put up a fence for now (until I can afford to build to full width) in the sides to where she stopped so she can enter and I block it , will the water company turn around and say they cannot access the drain and pipes so I will need to take it down which will cost me?
Infact neighbour might turn around and say she can’t access due to fencing-and any drain block will damage my property not hers!she never comes and check yeh drain. I don’t want the water company to come out and sort put on paper and record saying it’s only accessible via my side so it needs to stay open as all there concerned about it access to the pipes if needed

also I was thinking I will re route my waste pipes so I’m not using that drain that way it’s only hers and if it gets blocked it’s her problem but if it’s not shared I can’t call the water company to fix blocks as it will her responsibility as it’s only used by her and if I put up fencing so she don’t come onto my land if there’s a blockage she can’t fix it?

So annoying I now have to accommodate her! Want a way where I do what I want as I should be able to as long as working my boundary.

Im at a loss- her recently putting up that vent just brought back up my worry’s? She didn’t ask me permission to enter my land just did it
any ideas what I can do I would be so grateful sorry it’s such a long one 🙏🏽