The Cost of Moving Drains for an Extension: What to Consider

There are many factors that can affect the cost of moving drains for an extension. If you are intending to add an extension to your property, it will sometimes be necessary to move drains in order to ensure that they are not blocked or damaged by the construction, or that they do not exist in the same space as your extension.

There are important restrictions on where you can build an extension or other construction project in relation to public drains, and you may need permission from the local water authority before you start work. If you need to move a private drain as part of an extension construction project, you should also contact your water authority to learn whether you need approval to do so.

In terms of private drains, if a drain currently exists within the space where you want to construct your extension, you will probably need to move it outside this area. The cost of moving drains for an extension will vary significantly depending on the scale that the project needs; in some cases, it may be possible to simply move one drain and reconnect it to the main system with longer pipes, while in others, it may be necessary to dismantle and rebuild a part of the drainage system, which can include a lot of complicated pipes and connections.

What factors can affect the cost of moving drains?

There are a number of factors that can potentially affect the cost of moving drains:

The design of the existing system

Moving drains is likely to be more expensive if the current system design is unusual or complex. For example, do you have combined foul and surface water drainage, or are they separate? Does your property rely on a septic tank? Most modern properties do not use septic tanks and will have separate foul and surface water drainage systems, but each of these elements will affect the complexity of moving the drain, and therefore the overall cost of the project.


Heavy machinery is usually necessary to dig up drainage systems, so if your property has good access for vehicles and other machines, it will be much faster and easier to complete the work. If you are paying by the day, rather than a flat rate for the completion of the work, this will be a significant factor in determining the overall costs.

Restoration costs after the work is completed

Depending on the location of the drain, the moving process may involve digging up areas of your garden. So, while this may not be considered within the cost of moving drains for an extension, you may also want to consider whether you have the budget for landscaping to repair any damage done by maintenance work. Whether you feel this is necessary will depend on the scale of your extension or construction project, but it is worthwhile to consider.

Find out more

Lanes is the UK’s largest privately owned drainage and wastewater utility specialist, and we have significant experience with a variety of drainage systems and solutions. Whether you need a CCTV drain survey to determine the structure of the drainage network in the area earmarked for your extension, or you need advice on the specifics of moving your drains to another location, we can help.

To learn more about the services Lanes offers or how we can help to ensure the success of your drainage project, call us on 0800 526 488, or fill in our online enquiry form to arrange a call back.