Building and Developing

apartments surrounded by a canal with canal boats
Other developments
If your planned development requires a water main or sewer to be diverted, download our diversion application forms to keep your plans on track.


If you have an existing Hafren Dyfrdwy water main or sewer on your site you may need to apply to for it to be diverted. In some circumstances we can give permission for you to build close to or over a public sewer.


If you have identified a water main on your land which is owned and maintained by us and your development will affect it you will need to apply for it to be diverted. You will enter into a diversion agreement and Hafren Dyfrdwy will carry out the necessary work.

We don't give permission for any building to be built over a water main.

Download water diversion application form (PDF).


If you have identified a public sewer on your land which is owned and maintained by us and your new development will affect it you will need to apply for it to be diverted. Once you apply we will assess if we will need to carry out the diversion work or if you can enter into a self lay diversion agreement.

If you have a public sewer on your site and are making changes to an existing building that affect that sewer e.g. building an extension, we may in some cases give you permission to build over it. Find out more about this by visiting our build over sewers page.

Download sewer diversion application form (PDF).


If you require a disconnection at your property, here’s some information for you to find out more.

What is a permanent disconnection?

Your site may require a permanent disconnection. This is free - all we have to do is disconnect on the public boundary. So if you ever need the supply again, you’ll need to pay to replace the pipework, plus our normal new connection charges.

Things to bear in mind:

If your water supply also serves another customer’s property, then we might have to separate the existing supply first, and you would need to pay for this. In these cases, we normally do a site survey to estimate the amount of work and the costs. If you’d like to arrange this, please call us on 0330 678 1481 between 8.30am and 5pm Monday to Thursday, 8.30am and 4.30pm on Friday.

If the property is still occupied, we can’t disconnect the water supply. If this is the case, please let us know when the property will be empty.

The registered owner needs to give us authorisation for a permanent disconnection. If the person who fills out the form isn’t the registered owner, but you want a permanent disconnection, please include written authorisation from the owner.

After we’ve disconnected your water supply, surface water drainage charges for commercial properties might still need to be paid. This is because although the property is empty and no water will be used, it will still benefit from surface water drainage (removal of rainwater), which we provide. This has been approved by Ofwat.



To request a disconnection fill out form below