Rain on casurina

Is the tank working?

Research suggests that the answer to this question is likely to be no, or not at the moment, or it used to, or I just have to fix the pump first… Disturbingly, dysfunctional tanks are only the first barrier to using rainwater to solve some of our water usage problems.  Here’s a story I wrote on the subject for Brink a little while ago:


The water shortages and restrictions of the 2000s encouraged many people to install rainwater tanks. Joining those ranks of tanks are the ones installed in newly built houses to tick the boxes on the BASIX environmental scorecard. The result is millions of dollars worth of rainwater tanks across the country with a potential to massively reduce mains water use. But the reality is not matching the potential. Research suggests many tanks don’t work and most of the rest have limited use.

Social researcher Candice Delaney has been investigating practices and habits in households with rainwater tanks and discovered that water use is complex. For the past few decades, policy focus has been on the installation of tanks, but her research has shown that installing a tank is only the first step in reducing the strain on mains water. We also need to ensure that the tanks function, and are integrated into a range of water-use practices, inside the house as well as outside.

“If water-saving is the point,” she says, “we need to improve our approach to using rainwater tanks.”

Delaney, a researcher at the Institute of Sustainable Futures at the University of Technology, Sydney, found that up to half of tanks were not functioning. The pump is busted, the pipes are clogged, the first flush mechanism isn’t working, or a whole range of other problems has caused a malfunction that is yet to be addressed.

Christina Cleaver, who lives in Sydney’s inner west, is familiar with the problems of tank functionality. Large underground tanks were installed when her house was renovated four years ago. “They were linked to inside and we initially used the tank water for the washing machine as well as for the toilets. But the filter wasn’t good enough, the first flush device never worked, and we had to get a new pump. We had a water engineer help us at the time, but I’m not confident that he knew what he was doing.”

Getting the technology right in the first place is important, but so too is tank maintenance. Yet education and services around tank maintenance are non-existent.

The second critical factor identified in Delaney’s research is linked with attitudes to tank water and beliefs about the appropriate use of rainwater.

Research conducted in the Illawarra region resulted in a paper, “The ‘meaning’ behind household rainwater use: An Australian case study,” published in the journal Technology in Society. The study reveals the attitudinal barriers to a more effective use of captured rainwater.

Sydney Water estimates that a quarter of water consumption is used outside. Such use was the focus of water restrictions in the last drought, and of the 7125 households with rainwater tanks Delaney studied. She found only 5 per cent had done what Christina Cleaver tried to, in having rainwater tanks connected to internal plumbing. Yet not using a tank for indoor purposes means its potential is ignored for three-quarters of our water use.

Delaney’s study investigated some of the reasons for the low use of rainwater for flushing toilets, washing clothes and other inside uses by exploring the ‘meaning’ of rainwater. Delaney found rainwater was perceived differently by different people. Some respondents thought of rainwater and tank water as precious and pure. This is Christina Cleaver’s attitude. Cleaver, brought up on a farm where water was scarce, says that even though getting her new tanks operational has not been easy, she feels much better having them there. “I would put in a better system next time. I would love to use rainwater for showering, it feels like such a waste to use tap water.”

For most of those interviewed by Delaney though, tank water is not precious but dirty, and not appropriate for use in the house.

We seem to live with a range of mutually exclusive ideas about rainwater. It’s pure and natural, but only in the context of bottled water, or country retreats, or the rainshowers in luxury spas. When it comes to urban rainwater stored in a tank, many of Delaney’s interview subjects used terms like ‘smelly’ and ‘dirty’.

“This fits with the concept of the modern house as a safe, clean space,” she explains. Mains water is processed before it enters the house, but rainwater threatens to bring the pollution of the city and the urban rooftop into the house, and so is too dirty to use, even to flush the toilets, according to some of her respondents.

“The technology is constantly improving but perceptions are not keeping up,” says Delaney, adding that with climate change promising longer and more severe droughts we can’t afford to simply be reactive. “Rainwater tanks have enormous potential. Let’s improve the technology to help people get the best out of their tanks,” she says, “but let’s also challenge ideas about the appropriate uses of rainwater.”



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