National policy makers

Integrated Water Management Hub

Rainwater Harvesting

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Why is the project relevant to you?

Rainwater harvesting can reduce demand on public water supplies. Most studies have focused on household use, like garden water butts, however, recently Defra engaged with the water industry about commercial use. Our project looked at non-domestic properties and found benefits from retrofitting rainwater systems. Many commercial properties are suitable due to large roofs, space for storage tanks, and higher demand for non-drinking water.

Key messages for National policy makers

The project found that the amount of existing public water supply water demand saved was similar in both summer and winter. This might change our understanding of the effectiveness of rainwater harvesting during drier months.

1
Call to action

Retrofitting all commercial buildings with rainwater harvesting could save 23% (17,600 megalitres) of water annually in the Oxford to Cambridge area. While this is unlikely, it shows the potential benefits.

2
Call to action

Thinking about the various benefits of rainwater harvesting, like reducing storm overflows, makes investing in retrofitting these systems more appealing.

3
Call to action

Installing rainwater harvesting systems won't reduce the number of public water supply connections needed, because buildings will still need some drinkable water and backup supply.

4
Call to action

Rainwater Harvesting

Downloads
Report
Potential of rainwater harvesting to reduce public water demand in non-domestic settings in the Oxford to Cambridge Pan Regional Partnership Area
IWM