Make Rain Water Harvesting systems mandatory in all multi-occupancy new builds

In a country which experiences an average of over 33 inches of rainfall every year, we are missing out on an invaluable resource in rain water harvesting. By implementing this into all new builds and retrofitting these systems, the UK can massively reduce its fresh water usage, reduce water utility bills, reduce its carbon footprint due to reduced requirements of pumping stations, reducing flood risks. This is the equivalent to 203,099,262,300 liters, the majority of which could be utilized.