Is this really a public sewer?

[Tada]

Hi all

 

We own a semi-detached property and just had planning go ahead to build a 6m x 6m rear extension. Submitted application for building notice however they have identified that we are building within 3m of a public sewer and therefore need to convert from building notice to full plans and seek a build over agreement. Spoke to Thames Water - records indicate our neighbour has a public sewer, we have a lateral drain and therefore need to apply for a build over agreement.

 

Our property is one of 6 semi-detached properties served by a private sewage treatment plant (see pic). Sewerage flows from property 1 to 6 and then out to the plant, we are property no 3. The sewage plant is owned and maintained by a private company. We pay a monthly maintenance fee for this arrangement and are liable for repair costs (see pic). For this reason, I was not expecting this to be classified as a public sewerage arrangement.

 

When I follow the Thames Water guide, it states we don't need to apply for permission. https://www.thameswater.co.uk/help/home-improvements/what-do-i-need-to-apply-for#/what-are-your-plans

 

Grateful for any insights you have on this - are they right? Are they mistaken and should I challenge?

 

We had every intention to start groundworks next week!

 

Thanks

Tara

[Redbeard]

Where does your rainwater go?

[Gus Potter]

20 minutes ago, Tada said:

We had every intention to start groundworks next week!

Something to look forward to. 

 

21 minutes ago, Tada said:

records indicate our neighbour has a public sewer,

Just to be pedantic I'm assuming that your neighbour is one of the six houses served by the private treatment works. If that is the case then we can rephrase the question and direct this to the Thames Water. 

 

A public sewer is a Thames Water asset, so you need a buildover agreement to build over their infrastructure. If this is one of their assets then they have adopted that including the treatment plant and should be maintaining that at their expense. 

 

Ask them if this is a reasonable statement of fact and invite them to confirm. 

 

What may be the case is that you have a private agreement with the other home owners to share maintenence and upkeep of the shared private sewage system. You have a duty not to do something that will cost your neighbours extra money if there is a failure of the drainage system, say if your extension is badly built. If you want to build over then its your title deeds to look at and you may require your neighbours consent rather than Thames Water. 

 

Now it's a bit late in the day for this so if push comes to shove you may be able to take out for example an indemnity policy or just build it properly so you never have a problem. Now generally if the drain is outwith your founds then it's fairly simple, if within the foot print then you need to take extra care before you get the build underway.