Using Every Drop Twice

The cheapest new source of water is often the water we already have. Wastewater reuse treats used water to a high standard and puts it back to work for irrigation, industry, or even drinking supplies — turning a disposal problem into a reliable, climate-proof resource that does not depend on short-term rainfall.

Singapore's NEWater program now meets about 40 percent of the city-state's water demand by recycling treated wastewater, and aims to push that share higher. Israel goes further still, recycling close to 90 percent of its treated wastewater — most of it reused to irrigate crops, by far the highest rate of any country.