Extension closer to public sewer

[Waseem2024]

Dear All, 

Planning to buy a property but from searches, I found that there is a public Foul Sewer closer to the property (please see below image).

Do you think it is an issue? Does that mean we wont be able to extend on the side of the property (within 3 m of the sewer pipe) due to the water company owing this and need to get their approval?

 

and if they grant the permission, will that be too costly to move the pipe, etc?

 

Many thanks

[Mr Punter]

You may be able to extend at the side if you set the extension back.  It would be worth exposing the sewer pipe so you can see the actual depth and location.

[ProDave]

There will likely be an inspection chamber in the front garden where it changes direction.  Lift the lid on that and you should be able to find out exactly where it is and how deep, and the exact direction it runs, those plans are not always entirely accurate.

[Waseem2024]

Many thanks for your replies.

@Mr Punter: So there is no way I can build right from the front boundary of the house front? I know porch might be difficult/impossible to build?

 

@ProDave: I could not see any manhole and/or inspection chamber at the front of the property (it is not on the side (the area that goes to the garage), but will check on the front garden tomorrow). What I am gathering from the depth (sorry for the naive question), e.g. if it is too deep or a little deep, what information that would give me?

 

Many thanks, 

 

 

[saveasteading]

If it is a small shallow drain only serving the adjacent house then it's relatively easy and cheap to move.

If big or deep that won't be the case.

 

Don't assume you will ever get permission.

You need the neighbours' blessing too.

Allow £10k to £20 for a simple diversionbpkus you will/ may need professional help with permissions.

More if not simple.

 

[ProDave]

It looks to me just like the sewer serving 3 or perhaps 4 houses in total so I suspect it is just a 4" pipe and it may not be very deep.  Look for inspection chambers in your neighbours gardens that will at least help you pinpoint the exact location and ask them if you can lift the lid to see the depth.

 

The issue with building over a sewer is you don't want (won't be allowed) to do anything that puts pressure on the sewer  If it's shallow and your foundations would be lower than the sewer then perhaps you might be allowed to build closer to it as your foundations would not put pressure on the sewer.

[Waseem2024]

Many thanks, @ProDave and @saveasteading

Went a number of times to see if neighbours are in, but could not find them. The cover is on their driveway. 

That's a lot of money (10k to 20k) to move a simple/shallow pipe (as Saveasteading mentioned)

Will check with neighbors again.

 

Can I ask another question, the searches are back and in the searches it says that the overall flooding risk is low-moderate but Ground water is moderate-high. Is this an issue?

When I checked on the government website, it says "Flooding from groundwater is unlikely in this area." So very confused with this. Any ideas, please?

 

Also, is there any way to check wind and solar farms that are planned closer to the property?

 

Many thanks,

Edited December 15 by Waseem2024

[saveasteading]

40 minutes ago, Waseem2024 said:

Flooding from groundwater is unlikely in this area." So very confused

This means flooding from tivers etc. That doesn't look to be a problem

Low to moderate says the same.

 

42 minutes ago, Waseem2024 said:

wind and solar farms that are planned closer to the property?

How close troubles you? 

[Gus Potter]

Hope this helps.

 

There are three generic types of sewers.

 

1/ A private sewer. This serves your own house and belongs to you.. so you can do a lot. Now if you have a detached house this could run to the sewer in the road. Or you could be at the top end of a terrace.. if so there should be a rodding eye that allows for rodding of the drain along the back of all the other housese down stream.. you need to bear that in mind... keep the rodding eye accesible.

 

2/ A public sewer. These belong to the water company. These tend to be found along the line of a row of terraced houses at the back. But be aware that these can be deep if you live at the downstream end of the terrace. On occasion I find that these are not economic to get build over permission for if deep. I have seen sone at at least 3.0m  which make a rear extension far from viable moneywise.

 

3/ A main sewer. These are big sewers (call them pylons in electricity terms) and tend to be very problematic to build near.

 

Recomendations. Spend a £100.00 or so and get a utility search from an approved waterboard company.. could be Cornerstone etc. If you have 1 or 2 then it looks promising .. but check the ground levels. If 3 then make sure you get the place for next to nothing to cover your risk.

 

 

Edited December 16 by Gus Potter

[Conor]

1. Don't trust the drawing. It could be anywhere / not exist. I've worked in the utility sector, and specifically mapping side of things and they are rarely reliable. At our last property, the drawings showed a main sewer running right through all of the gardens, and if I'd trusted it, we would not have bought the house. In reality it was a further 8m back in an alleyway. You need to get somebody out to lift a few lids and tell you what is what.

 

2. It will likely be a small pipe serving just a couple of houses. Shallow, but easy to deal with.

 

3. Build over agreements are possible, you won't know until you have all the info and speak to the water company.

Edited Monday at 07:22 by Conor

[saveasteading]

5 hours ago, Conor said:

Don't trust the drawing. 

I've even shown utility companies mains services they didn't know were there. Not on any drawing.

 

It's seldom a good deal to buy a house in order to build an extension, unless you are a builder.

It's done to avoid moving usually, and the increase in value is usually less than the cost......and then there is the disruption and, in your case, the risk

 

[Gus Potter]

On 16/12/2024 at 07:21, Conor said:

1. Don't trust the drawing. It could be anywhere / not exist. I've worked in the utility sector,

True enough but we need a starting point. I suppose it's like asking a farmer for directions. "If you want to get to there don't start from here.."

[kandgmitchell]

The answer is to go to the relevant water company website. They will have a section on "build over" agreements. Most have a set of criteria for allowing extensions to be built over public sewers. If you meet those criteria (usually depth, size of sewer, manhole positions etc.) then some such as Anglian Water allow you to "self certify" that you comply and will allow you to build over. Then as mentioned above, source the latest information either from the water company itself or a company that supplies utilities information. You can then base your decision on the information available, although also as mentioned that information may not be perfect - our 150mm dia clay sewer at 1.7m depth was a 200mm dia pitch fibre at 2.0m........