Extension Built Over Public Sewage Pipe

[biddingwar]

Hello,

We are currently buying a property and the owners have stated that a public foul sewer pipe runs under a rear extension. There is also no build over agreement.

Does anyone have any experience with this? I can't say I know much about drainage and not really sure what my options are, what questions to ask or how concerned I should be..

Hmm I had a house like this. The neighbour’s child blocked their drains with toilet roll, the drain cracked and the foul sewage leaked into my subfloor space. It was a 1931 house so an old sewer.

Luckily it was a suspended floor but not very deep. We were able to access the drain by pulling our floorboards up but it was touch and go whether the patio would have to come up, too.

I was pregnant, it was Christmas, every time I put the heating on, we got this smell of foul sewage. I’d think carefully.

@Malteser71 thank you for your reply. If it was my just my drain I likely wouldn't be as concerned as know we are sensible, it's other people I am worried about. What room was built above the pipe if you don't mind me asking? Ours will be our kitchen which we will be putting in brand new along with new floors and the thought of it all having to be ripped out is horrendous!

Is it allowed? My neighbours built a conservatory over a public sewer pipe and had to take it down again

@Nahhh no it's not allowed unless you have a build over agreement which apparently they don't have! However this aspect we can get indemnity insurance for.

I am quite concerned now about what we are going to do and have already spent over £1000 on solicitors and surveys along with the stamp duty holiday we will lose £3500 if we pull out!

The sewer actually ran under a patio. We were going to build over it, but by luck we didn’t. It was a very expensive patio and I was horrified it might have to come up

I have just sold a ground floor maisonette which had this. The conservatory was apparently built over the sewer which runs along the back gardens along all the houses. There was a man hole cover in the back garden which didnt cause any problem and I knew nothing about it until we came to sell. We paid for an indemnity policy as there was no paperwork relating to the conservatory which had been built several years before I moved there.

@Noseylittlemoo we will definitely be asking for an indemnity policy too! Did the buyers do any checks of the drains?

I am thinking of asking the sellers to pay for a survey on the drains to confirm their condition..

Scary stuff. It's a risk so your decision will depend on your attitude to risk and also what other options you have. The likelihood of something awful happening increases the longer you stay there but overall my gut feeling is horrid stuff like @Malteser71 described probably happens no more than once in 10 years. It's just if shit happens it may be quite bad and may cost you quite a lot more than £3500 (if it happens of course which it might not). Beware of sunk cost fallacy.

@SecretOfChange I can't say I'm much of a risk taker! But we had our heart set on this house.

I really can't believe someone would build an extension over a sewer pipe!

@biddingwar no they were happy with the indemnity policy and photos of the manhole cover in the garden. I think the survey should cover the condition of the drains.

We pulled out on a house purchase because of something very similar. We found out very late in the day that the gorgeous kitchen extension had been built over the sewer pipe. To make it worse, the man hole cover was under the new kitchen with no easy access. When we pressed for more info, indemnity insurance etc, the buyers started to press heavily for exchange of contracts by the end of that week. We said no and pulled out.

Yes, it was money lost but thank goodness we did. We bought a better house on the same road a few months later. Drain house went back on the market and took another year to sell. The new owners have had an awful lot of problems with that extension, especially damp. I am so relieved. But gutted for the new owners.

@CagneyNYPD "drain house" made me laugh.

There is two drain covers to the side of the extension so would be accessible to remove a blockage but not a crack etc.

Indemnity insurance isn't going to make up for the awfulness if anything does go wrong! Why take on someone else's big mistake? Do you know if they didn't bother to get a build over agreement, did they build with adequately strong foundations etc? Do they have building regs sign off?

I'd probably ask for a CCTV survey, details of the sewer (how big is it/age/material/ how many houses does it serve, is there a manhole that could surcharge under your floor etc) & cost of indemnity. It in all likelihood could be absolutely fine and pretty much no risk.

Its not that unusual and I don't think build over agreements were required before 2011. If you have manhole covers to access the sewer then unlikely to be a problem I would have thought. As I understand it from a previous house purchase attempt (sellers pulled out on the day of exchange as they changed their minds about moving, but that's another story) a build over agreement would just require you to make sure there were manhole covers.

I agree get a CCTV drain survey and then form a view.

@PragmaticWench no I do agree! I guess they didn't want to spend the extra money on moving the pipe . From our enquiries it seems the extension has been there a substantial amount of time. The house is 1965ish and the extension maybe 10 years later. They said there is planning permission and we will wait for this in our searches.

@FurierTransform thanks for the suggestion, this is something we have been looking into. It's a small close, we don't think there would be anymore than 5 houses connected to that strip of houses and this house is in the middle so may only have 2 or 3 houses waste passing below it.

@SummerSaladsAreBack that's good to know, definitely got 2 manhole covers on our property and imagine would be covers on most of the properties.

Does anyone have any idea how far down a sewer pipe usually runs from the ground?

We are having the same issue where the current sellers are not aware of any sewage lines or man hole cover in the property. He is saying there is a man hole opening in the neighbour property. They lived in the house for 50 years and no issues happened so far. Looks like it is built over 50 years ago by the previous seller. Surveyor was not able to locate manhole cover. Water search shows sewage lines in the property. Solicitor confirmed there is no need of build over agreement since it happened before 2011. We are planning to build an additional toilet in the ground floor where we suspected the built over is happened. Now we are not sure how to take it forward. Whether it is going to cost hell lot of money if we go for additional sewer connection request or what would be the after effect. We like the house, only issue is with this sewage confusion. Seller is not ready to give any documentation/ support as he has not done any mistake from his side.

@NeedyShark What happened with your purchase? We are in the same position. We made an offer and found in searches that a public sewer running under extension. Seller does not know where is the manhole located but he said there is a one at neighbors which was used to fix a blockage 2-3 years ago. Not sure whether indemnity insurance would be enough here or not. I guess I might move forward with the purchase if at least there is an access to manhole in property because the built over was done before 2011 so built over agreement is not necessary. I don't think seller will be willing to provide CCTV survey neither I do because I have already spent enough on survey and solicitor.

Seller also did not get a building regulation for gas boiler installation done 5 years ago which is also another headache. Although my solicitor confirmed indemnity insurance will cover this if any enforcement action happened, I am uncertain if i need to regularize this I will lose the insurance and if there is any thing wrong with this work I will need to remove and redo it all over again.

I hope if somebody can advise me!
Thanks

In spite of the costs, I'd pull out.

If that blocks, you will have serious problems on your hands.