the most efficient way to regulate demand is through prices; as the price increases, consumers use less, and demand falls. In a recent survey of 1,600 households across ten countries, Grafton et al. found that price-based approaches are one of the most efficient methods of managing urban water demand2 (see Managing residential water demand in the OECD) (see Figure 1). An example of the successful use of pricing to regulate water demand is Denmark, where continued rises in water prices since 1993 mean they are now the highest in the OECD. As a result of the continued price increases, urban water use has decreased substantially from 155 to 125 litres per person per day, one of the lowest levels in the OECD.