Public sewer pipe within the boundaries of the property - diameter?

sad2k

Hi,

Drainage and water search results came back for the house I'm buying and they indicate that "there is a public sewer disposal main or lateral drain within the boundaries of the property" (running across the garden).

I had a look at Thames Water 'build over a sewer' guide (https://www.thameswater.co.uk/help/home-improvements/building-near-pipes) and there are different rules for building over those pipes, depending on the diameter and also apparently if it's "strategic sewer" you can't build over them at all (that's all assuming I'd want to build an extension).

I doubt that there is a strategic sewer running through the garden but still the question is - how do I find out what diameter is that pipe?

Unfortunately the map in the search report doesn't show it - see below.

Can I contact Thames Water to find out, or can I just assume it would be the smallest kind, given the location?

Thanks

Slithery

sad2k said:
...how do I find out what diameter is that pipe?

Measure it?

Grumpy_chap

Your link does not work - here is a corrected version:
https://www.thameswater.co.uk/help/home-improvements/building-near-pipes

That is almost certainly a lateral drain, and 100 mm dia. but you do need to check for certain rather than take what some random boke off the internet said.

You can contact Thames Water, either Developer Services or Property Searches:

https://www.thameswater.co.uk/developers/contact

https://www.thameswater-propertysearches.co.uk/ContactUs/ContactUs

They may charge and you should not have to pay again.  You have, I assume, already paid for the necessary property searches, and that fee is to give you the information you need. 
So, ask TW, as you may get a helpful person who just confirms what you need to know. 
In parallel, raise as a formal query to whichever company you paid to do the property searches.  If this has come via the Solicitor, it is just your Solicitor being lazy (though that is sometimes to your benefit as every "non-lazy" action a Solicitor does costs you £100 or more).

Good luck.

Section62

Grumpy_chap said:

That is almost certainly a lateral drain, and 100 mm dia. but you do need to check for certain rather than take what some random boke off the internet said.

Not wishing to be pedantic (it could make a significant difference to the OP) - the pipe from the boundary of 67/69 to the main sewer in the road is a public sewer rather than a lateral drain.

There's a question mark on what the pipe within the boundaries of 67 is because the location of manhole 601C would tend to suggest that is the head of the run, which if true would therefore mean the pipe on 67's land wouldn't be a public sewer at all, even though it is on the sewer map.

It is also possible that manhole 601C isn't the head of that run, and the sewer in fact continues unmapped behind 65/63/61, possibly also linking up to the manhole in the rear garden of 55.

sad2k said:

(that's all assuming I'd want to build an extension).

If the property you are interested in is number 67, and you might want to build an extension at some point in the future, then it would be a really good idea to get a CCTV drainage survey done before you exchange to find out whether the pipe in the back garden only serves 67, or if it continues on to 65.

If it only serves 67 then it is private and you can do what you want with it (subject to building regs).

If it carries on to serve 65 (and beyond) it would be public, and you are likely to need to cover the cost of a diversion, which (given the layout) might be more complicated than usual.

sad2k

I thought most sewer pipes were public since 2011?

https://www.thameswater.co.uk/help/home-improvements/ownership-of-private-sewers-and-pumping-stations

Section62

sad2k said:

I thought most sewer pipes were public since 2011?

It depends what the pipe does and where it is.

i) If the pipe serves more than one property then it will be public (unless exceptional circumstances apply)

ii) If the pipe only serves one property then it is private up to the point it crosses that property's boundary (with some exceptions)

iii) If it is a main or trunk sewer, or was individually adopted, then it will be public in all cases.


So looking on your map extract, 69 and 71 have a public sewer because the pipe is serving more than one property (i).

If the pipe in the garden of 67 only serves 67, then it will be private because none of the 3 conditions apply. But when that pipe crosses the 67/69 boundary it would become public because of (ii).

If 65 or any other properties connect to the manhole or pipe in 67's property, then 67 has a public sewer because of (i).


Can you confirm you are looking at buying 67?  If so, do you have a picture of the back garden you can share?  One possibility is the drainage for 65 might go straight into the manhole in 67's garden - which would explain why this pipe is recorded as a public sewer.  The other possibility is the sewer continues along the rear of the properties 65-61 etc.

kungfu_navs

Just to add that Thames Water has a chat function on their Facebook page and when i used it last was very quick to chat to someone and was very helpful in helping me located drainage on a property i was looking into. 

Section62

kungfu_navs said:

Just to add that Thames Water has a chat function on their Facebook page and when i used it last was very quick to chat to someone and was very helpful in helping me located drainage on a property i was looking into. 

They do, but the TW staff can only talk about the information they have in front of them. When it comes to the smaller drains and sewers in people's gardens the information is very limited, and a lot of what there is can be wrong.

For example, the map suggests numbers 61 to 65 don't have public sewers, and a TW member of staff would be looking at the same plan, so is likely to confirm that is the case.  However, by looking at the neighbouring properties it appears very unlikely that 61-65 aren't connected together - and the only way of confirming or otherwise would be to get a drainage survey done.

sad2k

Yes I'm looking to buy 67 and looking again at the photo of the garden it seems there are 2 manholes ?! Why would this be the case?

Section62

sad2k said:

Yes I'm looking to buy 67 and looking again at the photo of the garden it seems there are 2 manholes ?! Why would this be the case?

That close together I'd expect one to be foul and one to be surface water.  But the only way to be sure is to lift the covers.

Does 65 have some kind of drain against the wall (partly obscured by the plant)? Or is that drainage for the patio?

The positions of the manholes also make it feasible they carry on into 65's garden.  Do you think you might be able to find pictures of that? (E.g. on Rightmove/Zoopla)

sad2k

Section62 said:

Does 65 have some kind of drain against the wall (partly obscured by the plant)? Or is that drainage for the patio?

Full image attached - I don't think there's a drain.

So if this does go into 65's garden does this make it any more problematic for me? (apart from having to relocate 2 of them if I were to build over) [to be honest we're unlikely to build an extension in any case here but I guess if we were to sell later, the buyers might want to]