Following the changes made on 1st October 2011 the following applies regarding ownership of underground drainage serving dwellings;
A drain (single pipe) serves a single property and lies within the property boundary. (Not called a sewer, as a sewer serves more than one property).
The building owner has sole responsibility.
Lateral Drain (public)
The part of the private drain (serving a single property) that lies outside of the property boundary under public land (the highway, footpaths, verges) or private land. It connects to a public sewer.
Since 1/10/11 the Utility Companies are solely responsible (to resolve historic disputes between neighbours).
The part of the sewer on public land that serves more than one property.
The Utility Companies have sole responsibility.