Reducing waste of water
Implementation
In 1987, when the East Bay area in the USA was hit by a serious drought, exhortation and threats by the authorities did not manage to persuade the public to conserve water, and the consumption fell only marginally. Consumption dropped by a third and the reservoirs filled up only after they put up the prices for industry and agriculture - and for watering gardens and filling swimming pools - but not for normal household use. And after sending families tens of thousands of low-flow shower heads and water bags for cisterns, for free. In Boston, concentration on repairing leaks, putting in new shower heads and reducing cistern capacity resulted into drop of demand by a quarter, bringing it back to the level of 20 years earlier.
Claim
Selective metering of water - for example for families who use garden sprinklers - would certainly be effective.