Shared Sewer

[IDreamedISawStAugustine]

I live in a row of Victorian terraces houses. The houses all have shared sewers. Our next door neighbours are having building work done and as part of these works their sewer which was connected to the other neighbours sewer has now been connected to the one that runs via my house.

I was not consulted about the change to sewer and the reason why this was done is not clear. I am concerned this may cause problems with my drainage in the future.

There is a party wall agreement in place and on the whole the building works are progressing well. While in principle I have no objection to this change I am frustrated I was not consulted about these sewer works and want to make sure I am fully covered if there are any drainage issues in the future.

Who is responsible for private sewers is it the water authority or local council? Any advice or guidance from users with technical/legal knowledge or have experienced similar problems would be kindly appreciated. You tend not to think about where your foul waste goes on a day to day basis.

A private sewer is the responsibility of the home owner but only drains that serve your property are private since the private sewers transfer in 2015 (assuming you're in England or Wales). Once it's a shared drain it becomes the responsibility of the water company. The local authority are only responsible for surface water drains (road gullies), not sewage.
www.ofwat.gov.uk/nonhouseholds/supply-and-standards/responsibility-supply-pipes/

Thanks, Emma - that's very helpful. I am Wales/England. I spoke with my water authority today and they confirmed that a shared sewer is their responsibility. The homeowner is only responsible for the pipe to the shared connection. There is no issue with changing the connection but it does need to be approved and signed off by the water authority. They are checking if this approval has been sought and will be contacting me tomorrow to confirm.

If this join (change) is within 3m of your property, it should have been in the PWA. It’s a change that affects your property. Contact your PWA surveyor. You do have one, don’t you?

Yes, there is a Party Wall Agreement in place. At the moment I want to ensure that the Water Authority has approved and signed off on this work as ultimately they will be responsible for this service in the future.

The reason for moving manholes maybe they are adding new sinks or toilets into another part of the house.

If the builders are competent and the work will be been signed off by the water authority then I don’t see any reasons to worry that there might be issues.

From my own experience I can almost guarantee the builders own work will be at a higher standard than the water authority.

Frustratingly my Water Authority is now telling me that they cannot confirm if approval was sought and given to our neighbours because of GDPR. However, they have told me they will be directly contacting the property undergoing building works. I assume this is their indirect way of saying consent has not been sought!

I've had a similar conversation with Thames Water recently. Shared sewers are Thames water's responsibility. There is a good definition of what a shared sewer is on their webpages. Start by determining whether the pipe on your property is actually a shared sewer or not. If it was taking water from you and another property then it is 'shared'. If it only takes your water, then it is private.

How have next door connected to a pipe going via your property (or does the sewer run along the boundary line)?

If there was an existing pipe they have connected into then that is one thing. but if next door have laid a new pipe onto your property then you need to get legal advice, hopefully via your home insurance.

Thanks, Rollercoaster - they have not come on my property to connect to the sewer or lay a pipe. A lot of the information is second-hand via the onsite builders. When they first started the work they inspected my manhole cover and told me that the sewer egress was going via the other neighbour's house.

I assume that they must have the ability to connect to either sewer from their property. A builder told me because the other sewer was in a poor state they had decided to use mine instead which didn't sound right (I was pretty naive about sewer matters at that point but I am learning fast!). I have emailed the PM for the build for an explanation as some of the builders' explanations seem to contradict each other.

I have no objections to the works I am just conscious that the immediate neighbour and their neighbour have had problems with their sewers in the past while thankfully my sewer and that of my neighbour on the other side have been fine for many years. I do not want their sewage problems passed onto me!

I am hoping that my water authority will confirm that this work has been approved by them and carried out to the correct standards.

Discovered we have a shared sewer when we had a blockage. Meant we didn't have to pay the water board when they came to sort it out.

Do clarify the sewer runs. Because they've not come onto your land I'd guess that there was an existing pipe from your neighbour into the sewer you use. Perhaps it was only surface water rather than foul water, but that wouldn't matter if your area is combined sewage.

You've done the right thing checking with your water company, they must ensure the sewer has enough capacity to take the new load.

Do check they didn't tunnel under your garden though to connect. I recall a thread somewhere where that had happened!