water tank

Water wise for our future

Ensuring our water security is garnering increasing attention in the face of severe drought gripping parts of Australia. Does the housing industry have a role to play?


Laura Valic

The big dry is digging in its heels, made worse after a record hot summer. Water storages are down in every state and territory compared to this time last year, and WaterNSW reports Keepit Dam, north-west of Tamworth is down to one per cent active capacity, while other catchment areas across the state are at critical lows.


The last time we saw water stress on this level – during the harsh Millennial Drought from 1997-2009 – water security strategies changed across the country. As water storages fell to alarming depths and restrictions became part of everyday life, authorities looked to a number of solutions, such as behaviour changes, water-efficient appliances, rainwater harvesting and the construction of new water supply, such as desalination plants. However, these large-scale water facilities, capable of producing billions of litres of drinkable water, were not operational before the drought ended (and have only recently been switched on in a number of states after lying dormant for several years).


Data from the Australian Bureau of Statistics (ABS) also shows a jump in the percentage of households that installed rainwater tanks between 2004 and 2010, subsequently boosting the national figure to 26 per cent, about one in four homes.


Michael Smit, technical and sustainability manager at Kingspan Water and Energy, a division of global building products manufacturer, the Kingspan Group, says the water industry is in the midst of a debate over water provision. That is, what is more economically efficient and offers us better water quality and safety: large centralised infrastructure, such as dams, water recycling and desalination plants or a combination of much smaller centralised infrastructure and distributed solutions at the local level, through rainwater and stormwater harvesting?


‘Professor Peter Coombes and Kingspan Water and Energy are saying that the distributed solutions are much more efficient in some areas and that using a combination of utility water and distributed solutions offers real opportunities for our cities and buildings to work better within the urban systems,’ Michael says.


Harvesting rainwater has several benefits. It reduces the cost of water infrastructure across the urban system as well as stormwater management costs, and when combined with water-efficient appliances, it reduces household bills.

‘Rainwater falls on the roof of the building where you’re going to use it, so you’ve got very low transport costs,’ he says. ‘Because a roof is a non-trafficable area you’ve also got very few opportunities for contaminants so treatment costs tend to be low. In fact, you don’t need to treat it at all for a lot of non-drinking uses around the house.’

Captured rainwater is usually high enough quality to meet significant local water demand until it runs out, and it also reduces the negative impacts of urban water on natural catchments.

‘Once rainwater goes from the roof onto the ground or street it becomes stormwater with a different level of contaminants that requires a different treatment,’ Michael says. ‘But whether you capture it as rain or stormwater, the volume is really important. In all of our capital cities, more rain falls on the cities through the year than we actually use through our dams and treatment processes.’

Capturing rain at the individual lot level, even in times of below average rainfalls, eases the pressure on surface water supplies, which most of our cities generally rely on to supply residents. Michael says another benefit of distributed water sources is the decreased risk to the network.

‘Desalination, for example, isn’t reliant on rainfall but it has other issues because it’s a costly, resource-intensive process. It requires a lot of energy to make it work because you have to pump it from sea level up to the top of the local reservoirs and it’s also mechanically complicated,’ he says. ‘If you’ve got one very large desalination plant that supplies the whole city, if anything goes wrong with that single source then that’s a vulnerability. But if you’ve got thousands of water sources spread throughout the city, then you still have the whole network to rely on if a number were to stop working.’

There are some great examples of leadership in sustainable housing being shown within the industry


Originally from local government planning and building, Michael’s current role at Kingspan Water and Energy explores sustainable technologies in our buildings for water efficiency, alternative water sources and wastewater, and involves working with policy makers to remove barriers.

‘In some states we’re hearing from members of the building industry who are telling us that the cost of a rainwater tank adds too much to the cost of a new home. There is interesting residential property value research that shows that just having a rainwater tanks adds $18,000 to the value of a home.

‘A challenge for industry is to deliver a product that is going to give better water management for the people who are going to live in the house for the next few decades. We are working on some ‘Internet of Things’ hardware on tanks to assist with that.’

Michael adds there are some great examples of leadership in sustainable housing being shown within the industry, for example Mirvac, which has targets to capture as much energy and water as the house will need, essentially building self-sufficient housing by 2030.

Michael cited Roy Martin, sustainability manager from Frasers Property, who recently said the market is changing rapidly, and in order for the property industry to continue to support the Australian residential dream, green space and sustainability needs to be recognised as a key consideration in consumer demand.

‘We think there’s a real opportunity for the building industry to move into the smart sustainable home and city space, and be marketing their services and products as having the skills and knowledge to implement a long-term sustainable option,’ Michael says. ‘The homeowner is going to appreciate the benefits over a longer period of time because their water and energy bills will be lower. The operating costs of a home over time are actually greater than the building costs.

‘If you can be energy-, water-, wastewater- and stormwater-efficient at the lot level on a local scale, then you get these enormous collective benefits across the city and that kind of thinking is probably going to distinguish between the cities that do OK and those that are doing really well into the future.’

water tank

free flowing

Kingspan Water and Energy has been working on a number of innovations when it comes to rainwater harvesting.

‘We designed the High-Flow rainwater overflow system which goes on the side of a tank to handle very high flows (600 litres per minute) without the potential for overflow from the tank,’ says Michael Smit. ‘It’s designed to stop the common issues of flooding or dampness around a tank.

‘We’ve also found having a leaf diverter on downpipes is good for the behaviour of the whole system because it reduces the amount of organic material that’s going into the tank and sitting in a charged system. It’s important you don’t have organic material in that charged system because it impacts on water quality.’

Michael adds that Kingspan Water and Energy is also developing a low-cost internet-based ‘Sensor System’ to measure rainwater capture and use in each tank to make rainwater harvesting more accessible and the benefits more tangible for homeowners.

Kingspan Water and Energy

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