Installing a rainwater tank is practically mandatory for new buildings in NSW, but do people want them?

In NSW, new dwellings are required by law to meet a mains water saving target of 40%. While this technically doesn’t make rainwater tanks mandatory, it’s difficult to meet this target without an alternative water source, and rainwater tanks have proven to be one of the most popular ways of meeting the target, being the easiest, cleanest and safest option to install; with the largest water savings coming from having the tank plumbed internally for flushing toilets and laundry.

However, once the rainwater tank is installed, faulty installations or lack of maintenance often lead to the system deteriorating. The cost (real or perceived) of repairing the system is often deemed “not worth it”, making the water savings minimal if they continue to use the tank for the garden, or not at all if the tank is completely bypassed and mains water is used instead.

Poorly designed installations or maintenance of rainwater tanks can lead to overflowing pipes and tanks, algal growth, sedimentation, blocked pipes and/or a fouled water source.
Poorly designed installations or lack of maintenance of rainwater tanks can lead to overflowing pipes and tanks, algal growth, sedimentation, blocked pipes and/or a fouled water source. Photo credit: Sydney Water

Benefits of rainwater tanks

Aside from the obvious benefit in reducing your potable water supply, having the freedom to use water outside of any water restrictions or usage rules, and potentially saving money on your water bill, there is also the added benefit of using rainwater tanks for stormwater retention.

Many Councils now require additional stormwater retention before approving new developments. With increasing high-density areas in Sydney, there is also greater impermeable surface area, which means there is no soil for the water to absorb into, and leads to high volumes of stormwater carrying sediments and pollution, downstream flooding, and temporarily polluted water bodies.

By having a large enough tank, it’s possible to slowly drain a portion of the water through a small opening, preferably into a garden bed, to reduce the impacts of the stormwater while also having the rest of the rainwater tank for home use.

Photo credit: Sydney Water
Photo credit: Sydney Water



The emerging public committed and material green mindset demonstrates a cultural change that has taken place over time, and that there is a positive attitude towards water conservation, however upfront costs and lack of urgency present barriers to the adoption of rainwater tanks. The BASIX mains water saving requirement side-steps these barriers for people who can afford a new home.

From October 2002 to June 2011, Sydney Water offered rainwater tank rebates to customers, with larger rebates given to customers who installed larger tanks or plumbed the tank into their home for greater functionality.

Over 60,000 customers took up this offer. A qualitative study conducted on behalf of Sydney Water in 2008 found that the motivation behind acquiring a rainwater tank was largely based around environmental values, social responsibility and freedom from water restrictions to water the garden, fill the pool, and wash the car, pavement and the outside of the house/windows.

Without the urgency of water scarcity looming, and with the mixture of full dams, the lack of water restrictions and rainwater tank rebates, it would be unsurprising for the number of people to willingly install a rainwater tank to decrease, but the number of rainwater tank that are installed will continue to grow with new housing developments.

One factor that was found not to affect rainwater tank installations was maintenance. The awareness of rainwater tank maintenance was minimal; with most people assuming that no maintenance was required, at least for several years, and people that believed they were aware of maintenance didn’t really understand what was required for optimal tank performance.

Connection to laundry and hot water systems were not viewed favourably by customers, with perceived water quality issues on clothing and skin, however as more BASIX homes are built and connected to rainwater for laundry, it’s likely to become more acceptable as the social ‘norm’.


What’s next?

Overall, it seems that the requirement for new homes to be more sustainable is a good start to change, however there is more work that needs to be done. It is evident that, while retrofitters value their rainwater tanks, whether it be for environmental reasons or for the freedom to use the water without restriction, those who have installed a rainwater tank in order to gain development approval are basically disinterested or amotivated, as they haven’t researched or put much thought into their rainwater tanks as the retrofitters would have.

Having said that, it is also clear that the majority of people want to be environmentally friendly, particularly when it doesn’t cost them anything extra, and is relatively easy for them to do. The education and awareness of tank owners is essential in the success of meeting the goal of a mains water saving target of 40%. The increased awareness and knowledge of how their rainwater tank works, how to maintain it, and understanding of water quality, will help to assuage concerns over using rainwater for laundry and hot water systems, and also lead to better maintained tanks; ultimately increasing the overall effectiveness of the tank.

Community involvement and educational outreach activities to engage tank owners are imperative for the success of this program, and it has been demonstrated that communities are able to make significant water savings after some form of paradigm shift or education.

In Spain’s Zaragoza, citizens were able to reduce water use by 27%, despite a population increase of 12%. This demonstrates that community engagement can mean greater improvements than water restrictions alone, with ongoing benefits and social approval of good practices.

Although an educational program and community engagement is likely to be highly beneficial in increasing rainwater tank use and reducing failures, the question will be whether it will be funded, particularly while the dams are full and there is no immediate crisis at hand.

If it’s not funded now, but waits for an intense drought, how long will it take to a roll out a program, and for behavioural change to occur? And how many rainwater systems will be ruined to the point that it would be expensive, and unlikely for the owner to repair?

Rainwater tanks will fail unless they are maintained, but without education, maintenance is unlikely to occur. That it’s still a relevant and worthwhile endeavour, regardless of the lack of urgency at present? I’ll drink to that.

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