Advice request - buying house with foul sewer pipes

Davidben83

Hi everyone

I would be very grateful for advice on our prospective house purchase, please. 

The property is a semi that was extended in 2002 over two manholes (side and back extensions). The sewage map shows that there is a foul sewage pipe entering the property (as per the map, please see below). We assume that this means that sewage flows from the rest of the street to the prospective property where they connect to the main sewer. Is that a reasonable assumption?

We are keen to buy but are also likely to need to sell the house on in the not-too-distant future, so there is a worry over re-sale value.

The vendor states that no build over agreement was required at the time of the extension, which was done in line with building regs. On this basis, the vendor will not provide indemnity and stated that if we want a CCTV survey, it would need to be done at our cost. We are also concerned that it may be a pre-1936 pipe but do not know how to find out. 

We would be grateful for advice on how big a deal this is? 

Many thanks 

Section62

Davidben83 said:

The property is a semi that was extended in 2002 over two manholes (side and back extensions). The sewage map shows that there is a foul sewage pipe entering the property (as per the map, please see below). We assume that this means that sewage flows from the rest of the street to the prospective property where they connect to the main sewer. Is that a reasonable assumption?

Most likely it collects the flows from maybe 6 to 10 properties through the rear gardens, then flows out to the main sewer in the street.

Similar to the houses opposite with the 'L' shape - although in reality that one probably picks up the neighbour's and maybe a few more as well.

Davidben83 said:

The vendor states that no build over agreement was required at the time of the extension, which was done in line with building regs. On this basis, the vendor will not provide indemnity and stated that if we want a CCTV survey, it would need to be done at our cost. We are also concerned that it may be a pre-1936 pipe but do not know how to find out.

When was the house built?

Unfortunately there's a bit of a myth going around that build over agreements were not required before 2011. Possibly what the vendor has heard.

If the houses were built pre-1936 and have shared drainage then that means those pipes were already public sewers before 2011 and therefore a build over agreement would have been required (subject to the sewerage undertaker's local policy).

Davidben83

Section62 said:

Davidben83 said:

The property is a semi that was extended in 2002 over two manholes (side and back extensions). The sewage map shows that there is a foul sewage pipe entering the property (as per the map, please see below). We assume that this means that sewage flows from the rest of the street to the prospective property where they connect to the main sewer. Is that a reasonable assumption?

Most likely it collects the flows from maybe 6 to 10 properties through the rear gardens, then flows out to the main sewer in the street.

Similar to the houses opposite with the 'L' shape - although in reality that one probably picks up the neighbour's and maybe a few more as well.

Davidben83 said:

The vendor states that no build over agreement was required at the time of the extension, which was done in line with building regs. On this basis, the vendor will not provide indemnity and stated that if we want a CCTV survey, it would need to be done at our cost. We are also concerned that it may be a pre-1936 pipe but do not know how to find out.

When was the house built?

Unfortunately there's a bit of a myth going around that build over agreements were not required before 2011. Possibly what the vendor has heard.

If the houses were built pre-1936 and have shared drainage then that means those pipes were already public sewers before 2011 and therefore a build over agreement would have been required (subject to the sewerage undertaker's local policy).

Thank you for responding, much appreciated. 

We have tried to figure out when the house was built. Unfortunately, there is a discrepancy between the land registry records which has the property registered in the 1940s and the lender valuation which states it was built in 1920.   

Section62

Davidben83 said:

We have tried to figure out when the house was built. Unfortunately, there is a discrepancy between the land registry records which has the property registered in the 1940s and the lender valuation which states it was built in 1920.   

Have a look on old OS maps to see when that area was developed.  There's a good source here, and you can try different map layers to see what the area looked like at different times -

https://maps.nls.uk/geo/explore/side-by-side

The street layout and building outlines look typical of Victorian or Edwardian era development, maybe a bit later, so to me 1920 would be more plausible than 1940's.  First registration won't always represent the date the property was built.

A valuer, if they looked at the building, would be able to tell from one glance whether it was 1920 or 1940's - so I would put more weight on that.

Davidben83

 Section62 said:

Davidben83 said:

We have tried to figure out when the house was built. Unfortunately, there is a discrepancy between the land registry records which has the property registered in the 1940s and the lender valuation which states it was built in 1920.   

Have a look on old OS maps to see when that area was developed.  There's a good source here, and you can try different map layers to see what the area looked like at different times -

https://maps.nls.uk/geo/explore/side-by-side

The street layout and building outlines look typical of Victorian or Edwardian era development, maybe a bit later, so to me 1920 would be more plausible than 1940's.  First registration won't always represent the date the property was built.

A valuer, if they looked at the building, would be able to tell from one glance whether it was 1920 or 1940's - so I would put more weight on that.

Thank you Section62 for your advice and providing a link to the website, which is very useful. The valuer did look at the building. 

Would you mind letting me know how big an issue you think this is? We have now been offered a ten year indemnity by the vendor, which I do not think is sufficient. 

Section62

Davidben83 said:

Thank you Section62 for your advice and providing a link to the website, which is very useful. The valuer did look at the building. 

Would you mind letting me know how big an issue you think this is? We have now been offered a ten year indemnity by the vendor, which I do not think is sufficient. 

It partly depends on what exactly the indemnity covers.  Is the vendor now agreeing that a build over agreement was needed? Why only 10 years?

In terms of risk, the main issue is what options exist if the sewer under the house collapses.  If there was a relatively straightforward alternative route for the sewer to be relaid then the situation is possibly not so bad.  Looking at your plan, there doesn't appear to be any obvious alternative route, and that's before taking into account the fall of the land and depth of the main sewer.

There are 'no dig' and tunneling techniques which could be used to repair or replace the sewer, but they are expensive and access would be needed at both ends.  Assuming the side extension has blocked all outside access to the rear garden that would mean all plant, materials and workers traipsing through the house.

Then there's the question of where the pipes are.  If the extension has been built over the top of the manholes there's a good chance it isn't only the sewer running towards the road which has been built over, the ones running to the side(s) (i.e. parallel with the road) are probably under it too.  The point of access for carrying out any maintenance or repair is likely to be under the floor of the extension.

An indemnity policy might cover you against the costs of rectification work, but check to see what it says about your personal inconvenience.  Don't underestimate the domestic impact of sewerage workers using breakers to drill holes in your floor.

Finally, on a related point, you need to find out what "in line with building regs" means.  That doesn't mean the work had BC approval or sign off, which is probably unlikely to have been given with two public sewer manholes under the floor.  If the work hasn't had BC oversight then in conjunction with the sewer issue this is not a property I would buy.  There's no way of knowing what shortcuts might have been taken.

macman

Does the building have cavity walls? Very few houses built in 1920 would do, but almost all would be from the 1940's onward.

Doozergirl

A photo of the house would help.  The shape of the semi detached houses looks more 1930s onward with the wide bay windows... I'd also rely on the deeds more than a valuer, given the state of the valuation survey that was done on our house by a 12 year old 😬.   Often the deeds will describe the land being transferred before the house is even built.    What does that say? 

The CCTV survey is really your friend here as that is going to prove the condition of the pipes better than any assumption. 

I think Section62 is sailing away a little bit by assuming the house is pre-1936 and that building control weren't involved.   Let's establish facts first, otherwise we're just confusing you.  

Section62

Doozergirl said:

I think Section62 is sailing away a little bit by assuming the house is pre-1936....

I was assuming the OP has checked the old OS maps as suggested and confirmed this.

But if not, yes, further investigation is needed.  Depending on where in the UK this is, one plausible scenario to explain the date discrepancy is some 1940's rebuilding of bomb-damaged properties.

Doozergirl said:

....and that building control weren't involved.

There was a 'you need to find out', a 'probably', and an 'if' in that paragraph. 

Doozergirl said:

Let's establish facts first, otherwise we're just confusing you.  

I wouldn't wholly disagree, but the sewer plan does show a public sewer within the boundary of this property, and others in the street.  I wouldn't say that was absolute proof that a public sewer is there and a build over agreement was needed though.

There is a further consideration - that it is the age of the sewer which will determine whether it is public or not. A house being built on the land after 1936 won't make the sewer private if it existed and served more than one property prior to 1937.

To prove it wasn't public and no build over agreement was required would involve checking the age of every property connected to the sewer and confirming nothing was built on any of the plots prior to 1937. (Section 24 also applies to some post-1937 properties to further complicate the task)

That shouldn't be the OP's concern though.  If the vendor wants to refuse to provide an indemnity because the sewer wasn't public at the time the extension was built then it is up to the vendor to prove that.  It is reasonable for the OP to err on the side of caution and assume the sewer was public in 2002 and give the vendor the options of providing the contrary proof, or a meaningful indemnity.

Establishing as fact whether or not the sewer was public in 2002 is unlikely to be possible without the sewerage undertaker's help - which would mean the indemnity route would be null and void.  So the OP is going to have to rely on some assumptions if they go ahead with the purchase.

Bonniepurple

Section62 said:

Davidben83 said:

We have tried to figure out when the house was built. Unfortunately, there is a discrepancy between the land registry records which has the property registered in the 1940s and the lender valuation which states it was built in 1920.   

Have a look on old OS maps to see when that area was developed.  There's a good source here, and you can try different map layers to see what the area looked like at different times -

https://maps.nls.uk/geo/explore/side-by-side

The street layout and building outlines look typical of Victorian or Edwardian era development, maybe a bit later, so to me 1920 would be more plausible than 1940's.  First registration won't always represent the date the property was built.

A valuer, if they looked at the building, would be able to tell from one glance whether it was 1920 or 1940's - so I would put more weight on that.

Thanks for that website Section62.  I’ve just gone done a fascinating rabbit hole and discovered that my Dad’s house was built on a golf course and that our new house is named after a long gone farm.  I have a feeling that it is going to turn into a rather large rabbit warren!

Davidben83

Hi Section62, Doozergirl and Macman 

Thank you so much for responding and your help, it is much appreciated. 

The property is in north London suburbs, I have uploaded a picture. It is the pastel coloured house to the right. 

We have just realised that there is a third manhole in the front drive (covered by the car in this pic). 




The map comparison tool has been very helpful and quite fascinating. It shows that the road itself existed by 1920 with some, but not all, houses built. I have also found another map below from 1919-26 which indicates that the house was built on what was previously a road (circled).   



The vendor has provided a signed certificate of completion signed by council building control, dated 2002. 

We are concerned that there may be significant sewer/pipework under the property as it was built over an old road. 

Grateful for any further thoughts or advice. 

Many thanks