A SuDS attenuation crate is a modular underground plastic structure assembled from interlocking cells to provide bulk storage of surface water during heavy rainfall events. The crates retain run-off temporarily and release it at a controlled rate to sewer, soakaway or watercourse via a flow control device. UK installations follow BS EN 13598 product standards and CIRIA SuDS guidance, and the system is widely specified across Greater London new builds under Building Regulations Part H3 and London Plan requirements. Crates are typically wrapped in geotextile and surrounded by graded stone bedding, with access points for inspection and cleaning. The system is identifiable on construction drawings by its grid plan and depth annotation. Maintenance requires periodic vacuum cleaning of the inlet sump and inspection chamber to remove accumulated silt and prevent loss of storage capacity.
SuDS attenuation crate
Underground modular plastic crate system storing surface water for controlled discharge.
