There is an easy way to make rainwater usage economic; put up the price of reticulated drinking water (beyond 400l/day/household) to the marginal cost of production. The marginal cost of water is now the cost of desal as for one reason or another no more dams will be permitted. By putting in place this price signal people's ingenuity will find the optimum way for each to conserve, recycle or catch water. This freedom of individual action is much more effective than mandating water tanks or other command driven responses. Bacci
