We own a house in England that is approximately 100 years old. Our neighbours' property was built after ours.

Our water supply pipe runs from the water main, across our neighbours' land, and supplies our property. We understand that it is a private supply pipe.

Our neighbours are proposing to build an extension over the area where theirs and our pipe runs. We are concerned that once the extension and foundations are built, the pipe could become inaccessible if it leaks or needs repairing or replacing in the future.

We do not know when the pipe was first installed, and we are considering whether older deeds or historical records might establish any rights.

A Party Wall process is currently underway, and both surveyors are involved. We want to make sure the water pipe and our legal rights are properly considered before the extension is built.

Our questions are:

If no easement appears in the current title registers, could an easement still exist because of older deeds, the circumstances in which the properties were divided, or long-term use?

As the neighbours are proposing to build over the pipe, should they be expected to investigate whether their proposed works would interfere with any existing legal rights?

Can the Party Wall Award require suitable measures to protect the pipe, or is this entirely a separate property-law issue?

Would protective sleeving or ducting be an appropriate solution, and how can future access for repairs or replacement be secured?

If the neighbours refuse to investigate their legal position, would we have to pay for our own solicitor to establish our rights, even though the issue has arisen because of their proposed extension?

If the pipe needs to be relocated because of the extension, under what circumstances could the neighbours be responsible for the cost?

We do not want to prevent our neighbours from extending unnecessarily, but we also do not want to be left without a reliable water supply or with future repair costs because the pipe has been built over.

We would particularly appreciate advice from anyone who has dealt with a similar situation involving a private water supply pipe, an extension and a Party Wall Award.

I assume you have raised it with your Party Wall Surveyor ? That would seem to me a reasonable mechanism to address it - providing you have a good one.

When you say it is a private water supply pipe, what exactly do you mean ? That it doesn't connect you to a standard mains water supply provided by a water utility company ?

Is there a different route on your land only that could be used for the water supply pipe ? It sounds like the pipe may have been in place for a very long time - perhaps even a 100 year old lead pipe ? So you could consider this an opportunity to relocate the supply pipe onto your land and to upgrade it to a modern MDPE pipe with a larger bore than an old leap pipe, and to do away with any lead contamination to your water supply. As they will be digging trenches for their extension, your neighbours could be agreeable to digging the trench you would need on your land for the new pipe routing. After all it benefits both properties by removing an awkward interdependency. As you would benefit from an improved supply, perhaps you could pay some of the cost e.g. for the pipe, and/or the reconnection charges.

Nobody with half a brain would consider doing this without moving both the supply pipes to the outside of the footprint of the new extension.

Pipe is cheap, get two new supplies run in, they will probably damage the existing pipe whilst digging anyway so better to move them.

What does it say in your deeds, do you have a right of passage for this pipe or was it just a handshake type arrangement years ago.

The time you talk to a solicitor you could have chucked a couple of hundred quid at the builder and got a new one put in.

Edited 1 hour ago1 hr by Russell griffiths

There are a few gaps here. Assuming the OP's house was there first built in say 1926. Water pipe (lead or galvanised steel) runs to company main probably in the closest road. Between then and now a parcel of land gets detached and sold to a third party to build a second house. You would expect the seller of the land (presumably a previous owner of the OP's house) to reserve the right of access for their own services and that should be a matter of record. If so that should be recorded in the Land Registry entry for the newer house at least. Look there first for £6 (I think - but it's low).

Ducting the existing pipe through any foundations ought to be a given. Secure it in the Party Wall Award but normally the BCO would (should) ask for this to be done anyway.

Finally I agree with Russell above, talk to the neighbour and see whether you can negotiate laying a new plastic pipe to avoid their extension and out to the main. Most water companies will disconnect a lead supply pipe and connect a new plastic pipe for free if you bring the pipe to the termination (subject to application and their requirements as to depth etc), certainly Wessex did and United Utilities do.