This website uses cookies to enhance your user experience. By using this website you are consenting to this.

close and accept

Alex Hickman

10 Nov 2022

Why Invest in Rainwater Harvesting?

We asked Jason O'Loughlin, Technical Director at Waterman's Building Services to help us explain the importance of rainwater harvesting technology for sustainable industrial and commercial construction in urban London.

Drought in London

This year London experienced the most devastating drought since 1976 with many analysts believing that worse is to come.

The Environment Agency estimates that summer rainfall is expected to decrease by approximately 15% by 2050. For London to handle this decrease there needs to be an increased focus on water storage quantity as well as quality. Without capital investment directed towards increasing capacity and decreasing leakages, society as a whole will need to adopt water efficiency measures over the coming decade to protect against water shortages across London and the wider UK.

The impact of drought is often reported as a consumer problem but what about the impact on industry? Thames Water recently confirmed that “further restrictions on water usage for industrial supplies is on the cards if the drought continues.”


What role can the industrial sector play in mitigating the impact of drought? One solution for developers like KSP is to invest in rainwater harvesting.

Rainwater Harvesting

Rainwater harvesting is an engineering solution that collects rain in underground tanks as it falls from rooftops, runs off impermeable surfaces like asphalt yards or is absorbed by permeable parking surfaces. It is then stored on-site and recycled for re-use in the building’s WCs or landscape irrigation. The benefits are:

  • Water independence - Rainwater harvesting provides a free supply of water that is not supplied by the water utility.
  • Reduction in external water requirements - Less water is required from an external supplier to the building, reducing the stress on London’s water supply.
  • Reduction in water bills - By supplementing the supply from the local water company, water bills are reduced for the occupier. The rainwater harvesting technology that is installed in all our developments will deliver a reduction of 40%-50% in annual water use.
  • Sustainability - Rainwater harvesting, by reducing demand on supply, reduces stress on London’s water reservoirs.
  • Reduces flood risk and pollution - Heavy rainfall after a drought causes flooding, as the ground struggles to soak up the sudden excess water. Using rainwater harvesting helps mitigate flooding by collecting urban rainfall run-off and relieving pressure on the sewer system.

Future Proofing

In a future where drought leads to water restrictions, unplanned interruptions, increased water bills and serious flood risk, KSP is working with experts such as Waterman Group to install the latest technology to future-proof our buildings using rainwater harvesting. We do this to protect London’s environment, save occupier costs, and develop buildings that will not need to be retrofitted to comply with future environmental regulations. Resilience is embedded to protect against the increasingly predictable impacts of climate change.

Back to London Zero ’30