A lateral drain is the length of pipe that runs from the boundary of a single property to its connection with the public sewer. Since the 2011 private sewer transfer in England and Wales, most lateral drains became the responsibility of the sewerage undertaker, typically Thames Water in Greater London. The pipe inside the property boundary is still classed as a private drain and remains the homeowner's responsibility. This distinction matters when blockages or collapses occur, as it determines who arranges and pays for the repair. CCTV drain surveys are often used to confirm exactly where a defect lies relative to the boundary. Where ownership is unclear, water companies will usually attend and assess the line free of charge before allocating responsibility.
Lateral drain
Section of drain outside a property boundary serving a single building before the public sewer.
