New SuDS Standards 2025: What you need to know
Written by Toby Kay, Environmental Consultant
On 19th June 2025, the Department for Environment, Food and Rural Affairs (Defra) released the long-anticipated, new National Standards for Sustainable Drainage Systems (SuDS). This marks a significant development in drainage policy, with far-reaching implications for developers, planners, architects, and consultants involved in land and property development.
How do the new SuDS standards differ from previous guidance?
The new 2025 SuDS standards replace the narrower, hydraulics-focused 2015 guidance with a broader, multifunctional framework. The updated approach introduces seven national standards that give greater weight to water quality, amenity, biodiversity, and long-term maintenance, reflecting SuDS’ wider role in shaping sustainable, resilient places.
Where previous standards centred on peak flow rates and volumes, the new guidance recognises SuDS as critical infrastructure that supports urban design, improves air and water quality, reduces flood risk, and delivers both ecological and social value.
For property professionals, this shift formalises expectations once seen as best practice. Biodiversity net gain and amenity are now essential components of compliant drainage strategies. Water quality assessments and pollution control are also mandatory, particularly for sensitive sites.
At GeoSmart, we help clients navigate these changes with expert SuDS strategies and design that align with local authority and national requirements, supporting your project through planning and development.
Below, we’ve summarised each of the seven standards and what they could mean for your project.
What are the seven new National SuDS Standards?
1. Runoff destinations
Discharge must follow the drainage hierarchy:
- Collected for non-potable use.
- Infiltrated to ground.
- Discharged to an above ground surface water body.
- Discharged to a surface water sewer, or another piped surface water drainage system.
- Discharged to a combined sewer.
Evidence is required to justify use of lower priority discharge locations.
2. Management of everyday rainfall (interception)
Interception shall be delivered within the development for the first 5mm of rainfall for most rainfall events, for both winter and summer seasons.
3. Management of extreme rainfall and flooding
Establishes requirements for the design of infiltration features and allowable discharge rates to surface water features and/or sewers.
4. Water quality
Proposed SuDS shall be based on a robust water quality risk assessment and tailored to the pollution risks of the proposed land use.
5. Amenity
SuDS should contribute positively to placemaking, delivering aesthetic and recreational value in addition to drainage function.
6. Biodiversity
SuDS should support biodiversity gain, contributing to Biodiversity Net Gain (BNG), Local Nature Recovery Strategies (LNRS), and habitat connectivity.
7. Design of drainage for construction, operation, maintenance, decommissioning and structural integrity
SuDS must be designed with long-term operation in mind, including maintenance schedules, consideration of failure risks, minimal environmental harm, and assurance of structural resilience throughout the system’s lifecycle.
Are these new SuDS standards mandatory?
At present, the new standards are not statutory – they are not enforced via Schedule 3 of the Flood and Water Management Act 2010, which has yet to be enacted in England. Without Schedule 3, SuDS remain non-statutory and potentially ambiguous, relying on interpretation.
However, the National Planning Policy Framework (NPPF) expects Local Planning Authorities (LPAs) to promote sustainable drainage, and these new standards are likely to form the basis for LPA requirements and planning approvals.
For developers and planning consultants, meeting these standards is becoming increasingly essential to gain planning approval and avoid costly delays, revisions, or refusals.
What are the implications for development projects?
These standards raise the bar for drainage strategy expectations. The key takeaways are:
- Water quality, amenity, and biodiversity are no longer optional extras – they must be explicitly addressed.
- LPAs may require more detailed and holistic SuDS assessments to validate planning applications.
- Designs must show not just functionality, but long-term viability and community value.
- Projects without robust SuDS strategies risk rejection or delay.
How can GeoSmart help?
At GeoSmart, we offer expert guidance and detailed SuDS reports that align with the new national standards. Whether you’re at pre-planning, need support with design compliance, or want to strengthen your drainage strategy for LPA approval, we’re here to help.
Get in touch to ensure your project is compliant and positioned for success under the new SuDS expectations.
