When it comes to reducing water shortages in the UK, one idea scarcely gets mentioned: rainwater harvesting.
Rainwater can be drained off roofs and collected in storage tanks, which can be as simple as using a water butt fitted to a drainage pipe, and then used for watering gardens.
The rainwater can also be used for flushing toilets and washing clothes, which could save up to 40% of domestic water use – toilet flushing, for example, accounts for up to 35% of the average household’s water use.
The downside, though, is that without enough rain, the water harvesting system needs to switch to a mains water supply.
Rainwater harvesting is widespread in Germany, with more than 1.8 million households using rainwater, in a market about 300 times larger than that of the UK. The incentive is that householders collecting rainwater do not pay a drainage charge, based on the amount of water that goes down the drain.
Rainwater harvesting clearly helps to take the pressure off water supplies, but it also helps prevent big downpours overwhelming drains and leading to floods and sewage overflows into rivers.