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moving drains for extension

This week in our FAQ series, our property team advise whether a homeowner will need to communicate with their water provider about a new extension that could affect public sewers in the local area.

Q: I have a Victorian terraced property and want to extend the back of it further into my garden. However, in my garden there is a manhole cover with a sewer pipe that’s connected to my neighbour.

I paid my water company to conduct an asset location search to see if there were any public assets on my property, and they found none. If I complete my extension without damaging any sewer pipes, and maintain access to the manhole, will I still have to pay my water company for their agreement?

Are there any rules that I must abide by when building an extension over drains? 

A: Yes you will. So long as a pipe serves more than one property and is connected to the infrastructure of a drainage authority, it’s classed as a public sewer. There are many minor public sewers that run along the back of older properties like you describe. Because they’re relatively small, they do not always appear on maps.

If what you describe is correct, there is a public sewer in your garden that serves your neighbours and probably other neighbours too.

That means that, when you’re planning your extension you need to apply to your relevant drainage authority for a ‘building-over agreement’. This will ensure that the authority can access the drain when needed and check that your extension won’t damage the drain.

You may find that it’s possible to move the drains for an extension, or build an extension over the drains, but these adaptations would be done at your cost. Depending on your situation, it may make more sense to change your extension so that it’s more than three meters from the sewer.

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At Howells, our expert conveyancing solicitors are renowned across the UK. To find out more about how we can help you when buying or selling your home, visit our conveyancing page online today.


by Tristan Lewis


(Image: Torbakhopper under CC BY 2.0)

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