Climate change is likely to make water scarcer. Hotter summers will increase demand and increase evaporation from rivers and reservoirs. More of our rainfall falling in heavier bursts means that it is more likely to rush down our rivers to the sea rather than topping up our aquifers. And, since purifying and pumping water uses energy, if we can reduce the amount of water we use we conserve a precious resource and reduce carbon emissions. That sound good!