Building an Extension? How to Find the Drains on Your Property

extension on house where are drains

Drains. Probably the last thing on your mind when you move into a new house or decide to add an extension. In fact, unless your drainage system is blocked or you’ve noticed a foul smell, you probably haven’t given much thought to them at all.

Often it’s not until something goes wrong that we start to pay attention to our drainage system. But when something does go wrong, how can you identify where the problem is occurring?

Perhaps it’s directly below your kitchen sink? Or a build-up of hair in the shower? It could be something going on further down the pipes causing your outdoor drains to overflow. The problem may even be outside of your line of responsibility. But how do you find the drains on your property?

This question becomes even more crucial when we discuss building work. If you’re adding an extension or changing the layout of your home it is important to consider your drainage plan. Failure to do so could result in a burst pipe, which will put an immediate stop to your building work. As a general rule of thumb, if you are excavating any ground on your property – make sure you know where your drains are!

You generally have two options when it comes to finding the drainage system beneath your property. You can reach out to your local council and ask them to send you your drainage plan. The other option is to contact your local drainage experts and ask them to map your drains.

So what should you do?

Getting a Drainage Plan From Your Local Council

Asking the council to dig out your property’s drainage plan is brilliant if you’ve got a relatively new property and you don’t require the plans immediately. In theory, they should always have a copy of your plan on record so there’s no harm in asking.

Unfortunately, the plan will likely date back to when your property was built. In 2011, the UK drain laws changed which means a lot of existing plans were outdated. 

The most common reason for needing the plans for your drainage system is to identify where the line of responsibility ends, so if the plans that the council can provide have not been updated since the law change you’ll be left none the wiser.

The other thing you’ll have to bear in mind is time. If you’re trying to get planning permission for building work, time isn’t on your side. Therefore, requesting your drain plans from your local council might not be your best option. 

With the longer waiting times and uncertainty around the accuracy of the maps, the safest bet is to get your drains mapped by your local drainage expert.

Drain Mapping Services

If contacting your local council isn’t an option for any of the reasons listed above, you can reach out to your local drainage expert to get your drains mapped. By conducting a CCTV survey, the experts will be able to give you the up-to-date drainage plan of your property.

Drain mapping is often required if you are undergoing any building work, such as an extension. It is not safe for any work to commence before you have an understanding of your drainage system. If you were to dig through any pipework, the damage and cost to repair would exceed that of any drain mapping service. 

CCTV drainage surveys involve sending a small, high-tech camera down the pipework for a live feed of the complete system. Your drainage expert will closely monitor the footage, ensuring there are no signs of cracked or damaged pipes – very useful if you live in an older property or you’ve just moved into a new house.

Once the CCTV survey is complete, your drainage expert will be able to create an accurate drainage plan for your property. This drain map will outline all of the pipes under and around your home and tell you exactly where your line of responsibility ends. Once you’ve got that, building work can commence without the fear of bursting through any pipes!  


Illustration of a domestic drain map


How to Find the Drain System Beneath Your House:

Now you know that there are two ways of locating the drainage system beneath your house. You can either contact your local council and ask them for the plan associated with your property or you can contact a drainage expert who will conduct a CCTV drainage survey to get an accurate map of your drains.

Finding the drains running underneath your house is essential if you are planning any building work, particularly if the work involves excavation. The plan provided by the council will date back to when your property was built, so it may not be as up-to-date as you need.

When the UK drain laws changed in 2011, many people were left in the dark about where their line of responsibility ended when it came to drain repairs. The best way to get your drainage plan quickly and ensure it is accurate is to contact your local drainage experts and ask them to map your drains.

Maintain Drains provide CCTV surveys and drain mapping to residential and commercial properties in and around Dorset. So whether you’re buying a new house in Poole or looking to add an extension to your home in Christchurch, our team will be happy to help.

Simply get in touch with us for a no-obligation quote.


Q: Why might you want to get a drainage plan from your local council?

A: Getting a drainage plan from the council is useful for identifying your property’s drainage layout, especially if your property is relatively new.

Q: What changed in UK drain laws in 2011?

A: In 2011, UK drain laws changed, rendering many existing drainage plans outdated.

Q: What’s the common purpose of obtaining drainage plans?

A: One common reason is to determine the line of responsibility for drainage maintenance.

Q: What limitations might you face when requesting drain plans from the council?

A: The plans from the council may not have been updated since the 2011 law change, leading to potential inaccuracies and longer waiting times.

Q: How can drain mapping by a drainage expert be more beneficial?

A: Drain mapping through a CCTV survey by a drainage expert provides up-to-date information, particularly crucial when undergoing building work.

Q: What does a CCTV drainage survey involve?

A: A CCTV survey entails sending a camera down pipes to record live footage of the drainage system, revealing issues like cracked or damaged pipes.

Q: Why is it important to have an accurate drainage plan before building work?

A: Accurate drainage plans prevent accidental damage to pipes during building work and help identify the line of responsibility for repairs.

Q: What’s the recommended approach to finding accurate and current drainage plans?

A: The best way is to contact local drainage experts for a CCTV survey to map your drains accurately and efficiently.

This site uses cookies to offer you a better browsing experience. By browsing this website, you agree to our use of cookies.