SuDS stands for Sustainable Drainage Systems — an approach to managing rainwater that mimics natural drainage by slowing, storing and treating run-off close to where it falls, rather than piping it away as fast as possible. Most Irish local authority development plans now require SuDS measures in new development.
Conventional piped drainage moves water off a site quickly, which increases flood risk downstream and carries pollutants straight to watercourses. SuDS aims to manage run-off at source through a series, or 'train', of measures that reduce volume, slow the flow, remove silt and pollutants, and provide amenity and biodiversity benefits.
Irish local authorities apply SuDS requirements through development plan policy and planning conditions, and many publish their own SuDS guidance. For a single house, the requirements are usually modest: permeable surfacing, on-site infiltration and limiting the discharge rate.