The Drainage Hierarchy
All sites must manage surface water via the following hierarchy:
When managing rainfall, the SuDS network should be designed to match natural drainage routes, infiltration rates and discharge rates as far as possible. In addition to this, with concern over climate change and increasing risk of water scarcity, re-use of rainwater wherever possible should be utilised. Therefore, in accordance with the drainage hierarchy contained in Approved Document H of the Building Regulations, Planning Practice Guidance and the need to mitigate against water scarcity, all surface water run off must aim to be discharged as high up the following hierarchy as possible:
- Rainwater re-use (rainwater harvesting/greywater recycling)
- An adequate soakaway or other infiltration system
- Hybrid solution of infiltration and discharging to a surface water body
- To a surface water body (e.g. an ordinary watercourse)
- To a surface water sewer, highway drain, or other drainage system
- To a combined sewer
It should be noted that if out falling to public sewer or watercourse that is not in or adjacent to the development site then it is necessary to demonstrate permission in principle or third-party agreement.
Page updated: 17/02/2020