Before making an application, understanding where our sewer and water mains are located around your property is an important step to inform your options, as you may need to divert, build near to or over them. Our sewer and water maps are available to request online.
You can find information about our different applications below and each of our application webpages takes you through the steps the application will take and the documents you would need to submit. They’ll also cover the application costs and timescales so you can plan to complete your building works on time and to budget.
Building a new extension
If you are looking to build a new extension, it’s possible there is an existing sewer pipe near to your property. if your proposals mean building over or within 3 metres of our public sewers or lateral drains you will need to let us know through an application to build over a sewer, to ensure we are happy our pipes are protected and accessible in the future.
Alternatively, you might look to divert one of our sewer or water mains. Minor sewer diversions (a sewer < 225mm in diameter and < 3.0m deep) can be applied for under a Build Over application. For larger or deeper sewers, these can be diverted through a Developer Sewer Diversion (Where you can design and carry out the diversion work with our approval) or a Southern Water Sewer Diversion (Where we carry out the design and diversion work). The only option for water main diversions is for them to be carried out by us.
Replacing an existing supply
If you are replacing your existing water supply to increase your property’s flow demand or splitting it into, or from a shared supply, then you can apply for this through a water connection application.
Replacing a sewer connection by increasing your flows or making changes to the existing sewer connection will need to be approved by us before you undertake any works. You can seek this approval through a sewer connection application.
If you are connecting to our sewer network or mains supply for the first time, you can do this through a sewer connection or a water connection application.
Disconnections of existing water supplies can be made through our water connection page.