Roof water resource ignored
Collecting roof water is being suggested as part of the solution to stretching water supplies during a drought.
Saving rain from going down the drain is needed as climate risks to water supplies increase even in socalled water-rich countries like New Zealand, says Massey University Roof Water Harvesting Centre director Stan Abbott of Wellington.
‘‘Many regions experienced the adverse effects of a long, hot summer and because of the drought some local authorities imposed stringent water restrictions and encouraged householders to implement water conservation measures to lower the demand for reticulated water,’’ he said.
‘‘Inexplicably however, very few local authorities seemed to be actively encouraging householders to install rainwater tanks before, or even during the drought.’’
Roof-collected rainwater could be used as a nondrinking water source for toilet flushing, washing machines and for garden watering, he said.
Studies show rainwater tanks resulted in annual mains water savings from 18,000 to 55,000 litres for 1000 litre tanks and from 25,000 to 144,000 litres for 10,000 litre tanks.
Local authorities spend millions of dollars annually collecting, storing, treating and distributing drinking water to their communities and in the Auckland region alone, about 25 per cent of potable water is used in commercial and industrial buildings.
More than 10 per cent of the population depends solely on roof-collected rainwater systems for their drinking water.