What is a foul water drainage system?

foul water drainage in sub structure of build
Foul water drainage removes water from your home (Image credit: Roman Mykhakhuk/Getty Images)

When it comes to drainage systems for your self-build project, two of the most common terms you will hear are foul water drainage and surface water drainage.

While both involve removing water from in and around your property, knowing the difference between the two is important – least of all to ensure you don't cause environmental pollution or end up with unwanted sewage entering your home.

headshot of man with grey hair wearing work clothes
Brett Knowles

Brett Knowles has over 17 years experience in the plumbing trade and is an approved member of Checkatrade, meaning he has passed twelve rigorous checks and upholds Checkatrade’s six quality standard to ensure that customers can trust the trades to be who they say they are

Mark Stevenson
Mark Stevenson

Mark Stevenson has worked as a construction professional for almost 30 years and following an extensive career in housebuilding became managing director of Potton. He has a wealth of knowledge in all things related to self-build and extension. He is a regular speaker at the Homebuilding & Renovating Show and regularly writes for both the magazine and website.

Sarah Harley
Assistant Editor

Sarah is Homebuilding & Renovating’s Assistant Editor and joined the team in 2024. An established homes and interiors writer, Sarah has renovated and extended a number of properties, including a listing building and renovation project that featured on Grand Designs. Although she said she would never buy a listed property again, she has recently purchased a Grade II listed apartment. As it had already been professionally renovated, she has instead set her sights on tackling some changes to improve the building’s energy efficiency, as well as adding some personal touches to the interior.