Our house has an extension over a sewer... Is this legal?

Our house has a rear extension going over a drain and the flooring is cut so there is access to the sewer. Is this legal?
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Question: We recently bought a house with a rear extension going over a drain. The flooring in the extension is cut so there is access to the sewer. I have documents showing planning permission was granted, but is this sort of thing legal?

Answer: All drainage pipes which connect to the public network are now public sewers. However, where only one property is served by the pipe it is known as a drain and will be privately owned and maintained to the property boundary by the home owner. You appear to be unsure which you have.

If the extension was built over or within three metres of a public sewer there should be a build over agreement confirming your local water authorities approved the work. When you bought the house your solicitor should have undertaken a drainage and water enquiry — unless you were not having mortgage funding and specifically instructed them not to — which would have shown the presence of a public sewer with the boundary of the property, and if a build over agreement existed.

Your council building control department is responsible for control of building over sewers, but must consult the local water authority. The building inspector may require to see a build over agreement before signing off works. There may be planning consent for the extension but that does not cover a build over agreement. There should also be a building regulations completion certificate. Speak to the solicitor who acted in your purchase to see if he has any more information. Be aware that the water authority can access your property if it needs to maintain the sewer.

What's your problem?
If you have a question for Fiona McNulty, please email legalsolutions@standard.co.uk or write to Legal Solutions, Homes & Property, London Evening Standard, 2 Derry Street, W8 5EE. We regret that questions cannot be answered individually but we will try to feature them here. Fiona McNulty is a partner in the residential property, farms and estates team at Withy King LLP (withyking.co.uk).

These answers can only be a very brief commentary on the issues raised and should not be relied on as legal advice. No liability is accepted for such reliance. If you have similar issues, you should obtain advice from a solicitor. 

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