Saving Rain for Later
Collecting rainwater is not a new idea, but modern systems are making it easier to use in homes and public buildings. Water from a roof can be directed into a tank and stored until it is needed. It is often used for watering gardens or washing outdoor areas, tasks for (9) ________ drinking-quality water is unnecessary. In larger buildings, treated rainwater may even be used to flush toilets. This can reduce the amount of mains water a building depends (10) ________. The system has to be designed carefully so that dirty water cannot (11) ________ allowed into the drinking supply. Tanks also need to be large enough to hold water during wet periods without using a great (12) ________ of space. In places with long dry summers, rain collected in winter may run (13) ________ before demand falls. Even so, a well-designed system can make a useful contribution, especially in places (14) ________ water prices are high. As climate patterns change, architects are likely to pay increasing attention (15) ________ ways of storing water locally rather (16) ________ allowing it all to flow away.