Shared Drains in London: What You Need to Know
If you own a property in London, there is a good chance that you have a shared drain running through your land. These drains carry waste from neighboring properties, making them the responsibility of Thames Water for maintenance and repairs. However, when it comes to building extensions or making any alterations near these drains, there are important considerations to keep in mind.
One key issue with shared drains is access. These drains often run very close to the rear of buildings, and if you plan to extend your property, you may need to build over the drain. This can become problematic if access is required to fix any blockages or issues that may arise in the future. Imagine completing your beautiful extension, only to find out that access to the shared drain is now obstructed.
Not only is lack of access a concern, but accidental damage to the drain during construction can lead to even bigger problems. If you unintentionally damage the drain while building your extension, the responsibility for repairs falls on your shoulders. This might even result in the need to demolish parts of your newly built extension, causing significant financial and logistical headaches.
To avoid these potential pitfalls, it is crucial to follow the correct procedures when building close to or over a shared sewer. Typically, this involves ensuring that your foundations are at least 300 or 600 mm away from the drain, depending on its size and depth. Additionally, the foundations should be deeper than the drain to prevent putting any additional load on the fragile pipes.
In some cases, it may be necessary to relocate access points and inspection chambers, ensuring that Thames Water can still access the shared drain in case of emergencies. Access points cannot be inside the building, as this would hinder Thames Water's ability to carry out any necessary maintenance work.
If the conditions surrounding your build are relatively straightforward, your architect, structural engineer, or builder can self-certify the build-over agreement. However, if the situation is more complex, a formal build-over agreement must be arranged with Thames Water. This process may involve submitting detailed drawings, structural calculations, and possibly even inspections. It's important to note that this formal agreement can be both time-consuming and expensive, so it's always wise to be prepared for the possibility of it being necessary.
In most cases, your building control authority will notify the water board when a build-over or construction near a drain is likely. However, it is advisable to be proactive and anticipate the need for a build-over agreement ahead of time. By doing so, you can prevent unnecessary delays and costly design alterations during the construction process.
Navigating shared drains in London requires careful planning and adherence to Thames Water's guidelines. By understanding your responsibilities and following the correct procedures, you can avoid complications, ensure access for maintenance, and safeguard the integrity of both your property and the shared drain system in your neighborhood.