Purley Rise

Purley Rise is a development of four new-build homes on a sloping site in the London Borough of Croydon. EGY designed a sustainable drainage strategy that achieved 100% surface water betterment.

The site’s gradient shaped the drainage design. Tiered SuDS devices — soakaways, permeable paving, and a rainwater harvesting system — were arranged to maximise hydraulic efficiency on the slope, treating water at multiple points rather than relying on a single downstream solution.

The drainage strategy also corrected a historic surface water misconnection to the foul sewer. That connection had been adding surface water to the foul network for years, increasing the load on sewage treatment infrastructure unnecessarily. Disconnecting it was a straightforward but meaningful improvement.

Rainwater harvesting reduces potable water demand across the development. The drainage infrastructure is integrated with the architecture and landscaping: visible where it serves the character of the scheme, invisible where it doesn’t need to be.