A rubber gasket, often called a ring seal or O-ring, is the elastomeric component within a push-fit drainage pipe socket that provides the watertight seal between pipe and fitting. UK products comply with BS EN 681-1 and are typically made from EPDM rubber for sewerage applications, with NBR variants used where hydrocarbon exposure is expected. The gasket is identifiable on a disassembled joint by its black or dark grey rubber ring set into the socket. Correct lubrication during assembly is essential to prevent the gasket rolling out of position, a common cause of joint leakage on new installations across London developments. Over decades of service the rubber can harden and lose elasticity, particularly in PVC-U sockets exposed to UV light at chamber level. Replacement gaskets are widely available for common pipe diameters.
Rubber gasket (drain joint)
Elastomeric ring providing a watertight seal in push-fit drainage pipe sockets.
