Following the release of the updated National Standards for SuDS, we will provide surface water guidance for developers by the end of 2025. In the meantime, we recommend addressing each standard in a separate section of the Drainage Strategy.
As Lead Local Flood Authority, the county council is statutory consultee for surface water drainage for all major planning applications across West Sussex. This involves reviewing flood risk assessments and surface water drainage strategies.
Sustainable drainage systems (SuDS) aim to reduce surface water run-off from developments, mimicking the natural route that rainwater takes. You can find more information on SuDS on the Susdrain website.
Examples of SuDSs include:
- green roofs
- soakaways
- ponds
- wetlands
- shallow ditches or swales
- rain gardens or bioretention areas
- permeable pavement
Why SuDS are necessary
The National Planning Policy Framework states that all major planning applications require SuDS to ensure surface water flood risk does not increase within the application site or wider area.
You should follow national and local planning policy and guidance when preparing drainage strategies.
This includes, but is not limited to the:
- National Planning Policy Framework paragraph 181 and 182
- Flood risk and coastal change Planning practice guidance (PPG)
- National standards for sustainable drainage systems (SuDS)
- Flood risk assessments: applying for planning permission
The Flood Risk Management Team run a pre-application advice service.
SuDS design and adoption guide
We worked with our partner authorities to produce design guidance for developers which highlights the need to consider SuDS at an early planning stage.