TF7: Water supply
Typically in the UK, on average, about 225 litres of water per day falls on the roof of a house of 100m2. This is channelled and pumped from one place to another, then treated with the addition of chemicals before being pumped back to the houses.
As documented in this factsheet, to cut its ‘water miles’ Hockerton Housing Project collects all its water and treats it on-site, using separate processes for potable and non-potable water. Independent monitoring shows that it meets all relevant standards.