House I am buying is on combined sewer

[Pramodn]

I am in advance stage of buying a house and search revealed that combined sewer servicing adjoining two houses runs below the rear extension (mine is end of the row house). Current seller bought the house in 2012 with rear extension, and he has no knowledge of build over agreement. My solicitor has not been of much help in advising me on how to proceed. I am very confused on should I proceed with CCTV survey and indemnity or pull out. Any help is greatly appreciated. Also any recommendation of legal expert who can provide hourly advice on this please?

I'm from the US so in my information may not be applicable in the UK. Find out who is responsible for maintaining that line/connection. Is it a public utility or private responsibility?

Is there a "back flow diverter" (something that prevents the sewer from backing up on to you) on this section.

You need to at least get your questions answered or you need to back out.

I used to work designing sewage systems so with a bit more info I might be able to point you in the right direction.

When you say shared sewer, do you mean mains sewer or a treatment system.

In terms of build over, it should be part of the building control documents which the seller should have had and should be available. If not, they van apply to the building control office to get a copy.

If it is a shared run on a mains sewer (like a terrace run) then any blockages are usually the responsibility of the waste water company, this is normally the same company as your water supplier, BUT not always. In one area i did some work. waste is handled by Yorkshire Water whilst supply is Severn Trent. But the seller should give you that info.

@Ihatelittlefriendsusan thanks. This is shared run on a main sewer. Unfortunately seller has no build over agreement or building control agreement as rear extension was built as permitted development (it existed when my seller purchased in 2012). My worry is will the water supplier rip open the floor if any issue (blockage, drain collapse etc.) occurs in the future (current seller has lived for 12 yrs and he had no issues till date).

In 2011 all private sewers were adopted by the local water authorities who took on responsibility for maintaining them. If the extension was built before this happpened, then no build over agreement would have been needed as it was a private sewer at the time.

So probably no indemnity needed as no build over agreement was required in the first place . No CCTV survey required as it is the water authorities responsibility to maintain and not yours. (But check your drainage searches to confirm).

This is basic conveyancing stuff, and your solicitor is pretty hopeless if they can’t advise you.

@Doris86 thanks- my solicitor has been hopeless dishing out what i know already. As it was permitted development i have no record to pin point the rear extension but written response of the seller (response to the enquires raised). will that suffice?

If you can’t prove when it was built then an indemnity policy might be worth it to cover yourself, they aren’t expensive.

But don’t rely on what I’m saying. Get proper legal advice to confirm, after all that is supposedly what you’re paying your conveyancer for.

@Doris86 thanks

Google ‘2011 private sewers regulations’ for a bit more background.

@Doris86 sure will do.

Permitted development only means planning permission is not required. Building control sign off is usually still needed for things like lintels or RSJ's for example so it would be worth getting the seller to speak to building control. As the owner they are the only ones the info can be released to.

What sort of a house are you buying I.e. terrace, semi etc?

We wanted to install a conservatory in a previous property, just pre covid. That property was the end of terrace and the same connecting sewers, all draining towards and under our back patio. We had a man hole/hatch in the patio though. We were wrongly advised we needed a build over agreement, but in the end, needed to spend thousands to have the entire streets sewer pipe diverted around the conservatory. This is obviously current regs though, but if we'd known from the start- wouldn't have bothered at all.

I wonder if there is a man hold under the extension? Do you know if neighbouring properties have them in their gardens? If so, its likely there is one lurking under the extension. I'm afraid I can't advise on what has been there years, but I too am very surprised your solicitor isn't aware of the 2011 sewer changes.

@Ihatelittlefriendsusan it is end of terrace house. They brought it with extension 12 yrs back with indemnity insurance. My solicitor is saying extension by itself if fine as it has stated for long ( more than 10 yrs) so council will not ask to remove it.

@JC03745 man hole/ hatch is outside of property. I am thinking of CCTV survey to get additional piece of mind. Solicitor informed about 2011 changes but there is no document to confirm that extension is prior to that (. Than written response to enquires from seller). Hence my worries.

Whatever don’t get seller or you to speak to the local authority as you won’t be able to get indemnity insurance.

@pilates thanks. Agree we will not be reaching out local authority.

Will anyone actually do a CCTV survey for you of a sewer do you not own?

Whilst I understand your concerns, this is actually a very common situation and not something that really warrants considering pulling out for.

The house I sold this year had a similar situation. One of the solicitors questions to me was had the sewer been built over. I answered ‘yes’ and provided details. That was the last I heard of it, they obviously satisfied themselves they were happy with it and the sale completed with no further mention of it.

@Doris86 i have reached out to couple of them but waiting for confirmation onthem taking up the work. Did you buy any indemnity insurance please? I might be overthinking here, and playing too cautious.

I used to work for a water company on the sewerage side, though pre 2011 so I have no idea about current regs. However 99.9% of blockages can be cleared without digging down to the main.

A collapse is obviously different. But for any mains sewer collapse where the sewer has been in someone's garden I know we always had to reinstate the garden to what it was like beforehand. Never known a under an extension collapse. I suspect they'd block off the run under the extension and divert it round the extension as that would be easier and quicker than trying to do major building works through your extension floor.

Are you sure it's a main? Because you often have an individual short run of pipe going to a shared service pipe in a garden and then that runs to a main, normally in the street, sometimes in gardens. That's how my sewer is set up, next door has built over his bit of service pipe and has no manhole so has to come and rod from our garden when we get a blockage. My brother has a similar extension with a tiled floor and some fancy tiled manhole in the extension for access!

@DanielaDressen pardon me for my ignorance on terminologies. With what you are outlining clearly it is latter case (short run of pipe going to a shared service pipe in a garden and then that runs to a main, normally in the street)

We have the main shared sewer running behind our row of houses, too - with rear extensions built over them, all with planning permission. The sewer has inspection hatches in each property: as long as you can access these hatches and lift the covers, there's no issue. If someone has laid flooring over the hatch, that will have to come up if there's a problem.

Indemnity insurance wasn’t purchased, either by us when we bought the house or by our buyers when we sold.

When buying the house I remember talking to our solicitor about it. He was very blasé about it, saying we don’t know if there was a build over agreement but as it was done before 2011 there is nothing to worry about.

I've in this type of house for 30 years without any issues.

So the seller has indemnity to cover it? If so this may be transferable to you. When we sold the indemnity policies we had were transferred to our buyers on completion

@Okdaisy i am leaning towards accepting indemnity i will initiate discussion arnd this

We had a blockage in a shared drain. Where mains drainage is shared, the cost for sorting it out rests with the water company. Thames Water came out promptly, put down a camera and unblocked it without needing to dig up. The blockage was caused by a pipe defect under our neighbour's patio. Thames Water said they would have to dig up at some point and then make good at their cost, but not unless problem kept recurring.