The New Runoff Destination Hierarchy is Changing UK Drainage Design

The 2025 National SuDS Standards have fundamentally shifted how we approach surface water management. Gone are the days of defaulting to sewer connections – we now follow a clear hierarchy that prioritises sustainability and flood resilience.

The New Priority Order:

🌧️ Rainwater Harvesting – Transform "waste" water into a valuable resource for irrigation and non-potable uses

🏞️ Infiltration Systems – Soakaways, permeable paving, and infiltration basins that mimic natural water cycles

🌊 Surface Water Bodies – Rivers, streams, and constructed wetlands that support biodiversity

🚰 Surface Water Sewers – Only when sustainable options aren't feasible

⚠️ Combined Sewers – The absolute last resort

What This Means for Your Projects:

For residential developments, every new home should first consider rainwater harvesting. Commercial projects can leverage large roof areas for harvesting whilst incorporating permeable surfaces in car parks and loading areas.

The Planning Reality:

Local authorities are increasingly scrutinising drainage proposals. Applications that jump straight to sewer connections without demonstrating consideration of the hierarchy face delays or rejection.

Economic Benefits:

Whilst initial investment may be higher, sustainable systems often eliminate surface water drainage charges, reduce water bills, and avoid sewer adoption fees.

The shift represents more than regulatory compliance – it's about creating resilient communities that work with nature rather than against it.