While the core six statutory standards (S1–S6) established in 2019 remain the legal foundation, the 2026 update introduces significant technical and procedural shifts to align with more recent environmental legislation and climate data.

The key differences I can see in the 2026 version are:

• Updated Climate Data (FEH22): The mandatory transition to FEH22 rainfall data. Designs must now account for more intense rainfall patterns identified in the latest UK climate projections, replacing the older FSR or FEH13 models.
• Stricter Hydraulic Controls: There is a new emphasis on stricter runoff rate and volume control. This is designed to further reduce the risk of downstream flooding as urban areas become more densely developed.
• Prioritisation of Nature-Based Solutions: The 2026 guidance gives even greater priority to "green" SuDS like attenuation ponds, green roofs, and wetlands over traditional "grey" piped solutions.
• Biodiversity: While previously SuDS were seen as a "bonus" for nature, the 2026 guidance requires they contribute directly to the Net Benefit for Biodiversity targets and you must demonstrate that the SuDS scheme provides a measurable increase in habitat connectivity. Simply planting grass in an attenuation basin is no longer sufficient. You must use native species and create "stepping stone" habitats that link to wider ecological networks.
• Revised Design Tools: The 2026 update includes a revised surface water storage volume design tool. It now carries out direct hydrological and hydraulic calculations from user-provided FEH22 data. It removes the requirement for the "percentage impermeable" (PIMP) to be greater than 50%. The "Long Term Storage" calculation option has been removed from the simplified tool for complex designs.
• Lifetime Maintenance & Adoption: There is a stronger focus on long-term system performance. The updated guidance clarifies the SAB's role in ensuring maintenance plans are legally robust for the entire lifetime of the development, not just the initial adoption period.
• Application Fees & Process: Updated detailed guides for application fees were released alongside the standards to reflect current local authority administrative costs. 
  
  You can find a copy of the new guidance here.