If every home in South East Queensland had at least one 10,000 litre rainwater tank there would be no need to build any more dams in the foreseeable future! And there would be a lot fewer chemicals needed to purify dam water for drinking.
With rainwater tanks taking the first flush of any downpour there would be less pollution washed into our rivers and seas. The recent drought in South East QLD resulted in draconian water restrictions which spelled the death of many home gardens. Forecasts of the effects of global warming suggest that this kind of event will become commonplace in the future. Restrictions on the use of bore water means that this is no longer an available option. Currently, the only affordable option you have to drought-proof your garden is rainwater tanks.
You don’t need to be an Einstein to figure out that water is going to be more expensive in the future. Already we have seen the QLD government take over water resources and increase prices. Several of the newly-created Regional Councils have also significantly increased water usage charges. “User-pays” is now an accepted method of rationing scarce resources. The price of water is sure to increase more in the future. Having your own rainwater tanks can insulate you from these price increases and save you money.