Public Sewer within boundary

Public Sewer within boundary

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Dr_Gonzo

Original Poster:

959 posts

224 months

Friday 23rd September 2011
quotequote all
We're looking at purchasing a property and the drainage search has shown that there is a public sewer within the boundary (in the back garden). The map print-out is a bit unclear and doesn't show the exact position of the drain in relation to the house - it just shows a thick red line running through the back garden. On the map the sewer doesn't appear to run under the house but our solicitor thinks there's a chance that it may. The sewer runs through the back garden of the entire street and so if it's under ours it's under at least 10 other houses. Our solicitor is drafting a 'build over' agreement incase there is ever a problem in the future.

Has anyone else come across this and should we be concerned?

Also, we're hoping to extend a few metres into the back garden i.e. towards where the sewer appears to be. Is there anyway we can get a more accurate location of the sewer and if not, would the mere possibility of it being there jeopardise the possibility of having an extension?

Thanks,

The Doctor

Cupramax

10,469 posts

251 months

Friday 23rd September 2011
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Nextdoor neighbour in my old house had this problem and ended up having to re route the sewer when they built an extention. Im guessing you'd need to do a drainage survey or speak to the waterboard to find the exact position. Can you speak to the neighbours? Sewers tend to have regular manholes.

Dr_Gonzo

Original Poster:

959 posts

224 months

Friday 23rd September 2011
quotequote all
The house next door has an extension of the size we would be after, so I'm guessing they would have probably encoutered any issues when that was built (althougth it looks 15+ years old). Does a drainage survey actually entail a site visit or do they just look up the records? Because the drainage records are a bit vague.

Skyedriver

17,659 posts

281 months

Friday 23rd September 2011
quotequote all
I know its a house purchase so you don't know your "neighbours" but if you can have a look in the neighbours back gardens, you'll see a manhole cover somewhere, probably the end houses but not necessarily. A tall stick so you can see it (a ranging rod if you can get one) and you will get an approximation of the line, by joining the dots although the cover could well be a little offset from the actual pipe run.
A building over agreement is needed if you are "building over" the sewer but if the depth of the sewer is say 2metres then your building over if you are 1.999m away.
The likelyhood is that you won't have a problem if the sewer needs digging up in the future because of a problem, the water authority would likely carry out a diversion instead but you cannot guarantee that if there is no where to divert. Worse case scenario is they can simply demolish your extension....

Dr_Gonzo

Original Poster:

959 posts

224 months

Friday 23rd September 2011
quotequote all
Skyedriver said:
I know its a house purchase so you don't know your "neighbours" but if you can have a look in the neighbours back gardens, you'll see a manhole cover somewhere, probably the end houses but not necessarily. A tall stick so you can see it (a ranging rod if you can get one) and you will get an approximation of the line, by joining the dots although the cover could well be a little offset from the actual pipe run.
A building over agreement is needed if you are "building over" the sewer but if the depth of the sewer is say 2metres then your building over if you are 1.999m away.
The likelyhood is that you won't have a problem if the sewer needs digging up in the future because of a problem, the water authority would likely carry out a diversion instead but you cannot guarantee that if there is no where to divert. Worse case scenario is they can simply demolish your extension....
The garden of the house to the right of the property has been completely hard paved so either they've paved over it; it's in their garage; or there isn't one. The house to the left, the last house on the row, also doesn't appear to have a man-hole in it. Also, several houses to the right have also paved their entire garden, and as far as I can see there's no man-hole covers in any of the gardens. So now I'm a bit confused

Busa mav

2,556 posts

153 months

Saturday 24th September 2011
quotequote all
yuou will need a build over agreement if you propose to build over , or within 3m of the sewer.

If the sewer is a deep one then foundation depths for the extension will also be deep .

The borough engineers dept are normally very helpfull and have such information to hand smile

davidjpowell

17,767 posts

183 months

Saturday 24th September 2011
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I probably should not mention the public sewer that run underneath two houses (small terraced).

One day the sewer reached capacity and needed upgrading. Houses were compulsory purchased and no longer exist.

This was unusual, and as I understand it they were not the average sewer but 'fk off' big ones. But still I think I'd want to know a little more about where they run.

herbialfa

1,489 posts

201 months

Saturday 24th September 2011
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As Busamav said you will need to enter an "Eavesment Agreement" with your Local Water Board.

Costs about £400.

If you are within 3 metres of a public sewer Building Control will flag this up immediately if an application is submitted.

You then provide the Water Board with a accurate cross section of your proposal for them to agree.

In simple terms all you have to demonstrate is that the top of the foundations will be no higher than the lowest point of the sewer!

herbialfa

1,489 posts

201 months

Saturday 24th September 2011
quotequote all
As a side note....................

When I bought my bungalow we were informed that the whole area was affected with drainage problems due to the developers using some sort of "pitchmastic" pipes. 1964.

This material has started to fail etc and there are hundreds of claims in at the moment due to blockages etc.

The guy through the wall is the start of the drainage run, then through mine and onto about another 8 bungalows before it connects to the main sewer.

The guy who sold the property to us made us fully aware of the problem (his disceased parents bungalow) and we agreed that he would knock off £6K of the asking price! My first job when we moved in was to build a rear extension right over the sewer.

Was sorted out (groundworks) for about £200! New pipes, inspection chambers etc.

However bugger lugs through the wall didn't accept my offer, when the diggers here get yours sorted as well!

His man hole is near enough central to the width of the bungalow.

What has he done??????

Built 2 conservatories either side of the man hole FFS!

She sits in 1 and he sites in the other about 1 metre apart!!!!!!

Waving to each other.................

Steffan

10,362 posts

227 months

Saturday 24th September 2011
quotequote all
herbialfa said:
As Busamav said you will need to enter an "Eavesment Agreement" with your Local Water Board.

Costs about £400.

If you are within 3 metres of a public sewer Building Control will flag this up immediately if an application is submitted.

You then provide the Water Board with a accurate cross section of your proposal for them to agree.

In simple terms all you have to demonstrate is that the top of the foundations will be no higher than the lowest point of the sewer!
Excellent advice and spot on accuracy.

Do not contemplate purchase or extension until you have clearly understood the situation. The Public Sewer has to be protected and accessible and you cannot safely do anything without clearing the legal requirement first.

I have seen extensions demolished for just such reasons.

You Solicitor is your first point of call.

Dogwatch

6,222 posts

221 months

Saturday 24th September 2011
quotequote all
We've got two! First a sewer which runs along the back gardens and serves the neighbouring houses. This was constructed because the concrete road outside was laid pre-war and so when the estate was eventually built in the '50s running the sewer through the back gardens was about the easiest option. Most of the neighbours have extensions or conservatories which must 'bridge' the sewer and I warned my then new neighbours about it when they submitted plans for their extension. Still got approval but it turned out the actual line of the sewer across the garden was just where they had wanted to put the foundations! This one will become the responsibility of Southern Water from next month under the new legislation.

The second sewer runs down the side of the house (and adds a useful couple of yards to the width of the garden). This is a deep one which accepts the outfall from our garden sewer and several similar cross-sewers, plus our own contribution which goes straight into it biglaugh

Never had any problems with either in 25 years but were were warned that if we wanted to build beside the house Southern would insist on an agreement allowing them to demolish any such building if they had to get access to their sewer.

King Herald

23,501 posts

215 months

Saturday 24th September 2011
quotequote all
When we bought our house we noticed on the paperworks 'Due to a main sewer running through the property permitted development may be restricted' or words to that effect.

It showed a thick red line running between the house and the attached single garage, and there is also a corridor between the two, with block paved floor, which I assumed was because of the sewer.

I was unaware of the gravity of such things, and a year later build a rather solid garage in the garden, just off the sewer line.

A while later I did some block paving and discovered a covered man hole, and a main sewer under it, very close to the property line, and some 20 feet across from where the deeds say it is......

yikes

So, really we should have a build-over permit for where our attached garage was built, (built much later than the main house, but before we moved in) and our neighbour should have a build-over permit for the double extension he has built right up to the property line that covers the sewer.

And my new garage is built over the sewer as well.... frown

otherman

2,190 posts

164 months

Saturday 24th September 2011
quotequote all
Water Board....Borough Engineer....get up to date people.

The correct people to ask are the developer services people at you water company which I think is Welsh Water. This is the team that deals with building over issues and can advise what records they have, reliability and how to get a more accurate location. Knowing the size and depth of the sewer is important. Being a public sewer WW will have a right to come and work on it if there's ever an problem and that could mean a very big excavation if its a big deep sewer.

link to welsh water developer services website


Busa mav

2,556 posts

153 months

Saturday 24th September 2011
quotequote all
otherman said:
Water Board....Borough Engineer....get up to date people.
you need to get out on the street more smile

The old guy in the borough engineers dept will have more knowledge than any of the tossers at the water board.

They may have all the drawings to hand , but that normally will bear no resemblance to what actually happened on site .

King Herald

23,501 posts

215 months

Saturday 24th September 2011
quotequote all
Busa mav said:
They may have all the drawings to hand , but that normally will bear no resemblance to what actually happened on site .
As I discovered, main sewer was 20' from the marked line.

K50 DEL

9,227 posts

227 months

Sunday 25th September 2011
quotequote all
herbialfa said:
As a side note....................

When I bought my bungalow we were informed that the whole area was affected with drainage problems due to the developers using some sort of "pitchmastic" pipes. 1964.

This material has started to fail etc and there are hundreds of claims in at the moment due to blockages etc.

.....
Lucky you for being informed, I wasn't informed and have just had to have the sewer that runs through my back garden replaced for exactly this reason (my house was built in '64 also)
Cost me 700 notes but at least my manhole no longer floods once a month!

otherman

2,190 posts

164 months

Sunday 25th September 2011
quotequote all
Busa mav said:
The old guy in the borough engineers dept will have more knowledge than any of the tossers at the water board.
Actually the old guy at the borough engineers either retired or transferred to the water company when the sewerage agencies closed. Water boards haven't been around since 1974.

blueg33

35,574 posts

223 months

Sunday 25th September 2011
quotequote all
Dr_Gonzo said:
We're looking at purchasing a property and the drainage search has shown that there is a public sewer within the boundary (in the back garden). The map print-out is a bit unclear and doesn't show the exact position of the drain in relation to the house - it just shows a thick red line running through the back garden. On the map the sewer doesn't appear to run under the house but our solicitor thinks there's a chance that it may. The sewer runs through the back garden of the entire street and so if it's under ours it's under at least 10 other houses. Our solicitor is drafting a 'build over' agreement incase there is ever a problem in the future.

Has anyone else come across this and should we be concerned?

Also, we're hoping to extend a few metres into the back garden i.e. towards where the sewer appears to be. Is there anyway we can get a more accurate location of the sewer and if not, would the mere possibility of it being there jeopardise the possibility of having an extension?

Thanks,

The Doctor
Is an easement shown? A public sewer will normally have a 3 metre easement.

If you want to build and extension over the easement you will require a build over agreement. Shouldn't cost too much if you can use the water company's standard one.

I have done a few build over agreement and water company's are a PITA when it comes to getting them sorted.

If you are buying the house, your solicitor should tell the sellers that their title is defective especially of something has been built over the sewer, or if an easement is missing. You can then ask the sellers solicitors to get it sorted at their cost.

yorkiebrown

1 posts

73 months

Saturday 3rd February 2018
quotequote all
i have been reading some of the comments about drainage and where it goes under the buildings ,I have recently moved into a bungalow which I am building an extension only to find that I have a sewer pipe coming from next doors into a manhole in my garden which was covered over with shrubs etc,the sewer pipe is black pitch when looking at my drawings of the sewers this pipe is not shown ,I called the water people and they told me that if its not on there drawings then it must be a private sewer so I have put lintels over the pipe to start building ,but reading some of the past stories I'm a bit reluctant to carry on ,any advise would appreciated

normalbloke

7,401 posts

218 months

Saturday 3rd February 2018
quotequote all
The records (as others have suggested) are purely indicative. What it will usually tell you with reasonable accuracy is the type, material of construction and it's diameter and direction of flow. Assumption between manholes is just that. If it's a pumped sewer it is a whole different kettle of fish. Accurate location should be simple for any utility surveyor using radio detection techniques if it's metallic(unlikely) or a sonde and or GPR.
Good luck.