With drought gripping various parts of the country, awareness about the importance of efficient water use has grown markedly throughout Australia over the past decade.
Be that as it may, the hard-core case for strong water efficiency measures in commercial buildings is less clear cut than that for energy efficiency, especially at the more significant end of the scale in terms of investment such as on-site wastewater treatment plants.
Unlike energy, water is relatively cheap and the immediate benefits from a cost perspective associated with lower levels of water consumption are usually not large. Benefits associated with better water management initiatives are also rarely visible to building occupants and do not necessarily boost the productivity of the tenant’s workforce, unlike improvements to lighting or indoor air quality.
More extensive water measures such as blackwater recycling plants have limited impact in terms of improving building resilience or extending the building’s operating lifespan and indeed, and require expensive energy to run and spending to maintain. Compared with energy savings, water simply does not deliver the same punch in terms of benefits which are easily sold to prospective tenants or investors.
So where is the business case for water saving technologies, and what types of investments stack up in different types of buildings?
The case is most clear, engineers and design consultants suggest, with straightforward measures such as water efficient taps and shower heads. Cost savings associated with water consumption itself may not be overly significant, but outlays for these types of measures are small, whilst savings in terms of energy costs required for hot water should not be understated.
“Efficiency is the first step and the best thing to do is to make your fittings, taps, pipes and everything as efficient as possible,” Cundall senior ESD consultant Hannah Morton said.
Mike Dodd, a senior engineer at Arup, agrees.
“The best approach with public and commercial buildings is to reduce water consumption as far as possible,” he said. “That’s always the first thing you want to do.
“The strategy is always to reduce water consumption, and the best way of doing that is to look first at your low hanging fruit which is your fixtures and your fittings. If you’ve got an existing building, and you go through it and adjust and replace your fittings, you can make significant water savings before having to do anything else.”
Beyond fittings, the next step revolves around rainwater capture and storage. While perhaps not as beneficial in a taller office tower, this is certainly feasible in a warehouse or industrial environment with greater roof space and the potential to reduce water consumption and water costs to a material extent.
Finally, there is the recycling of water for re-use on the premises, most likely through greywater or blackwater plants. The main benefits of these are concentrated toward the higher end of the market and come in the form of higher NABERS water ratings and Green Star ratings. These can help attract higher paying tenants who are sensitive about their corporate image and thus have target sustainability ratings with regard to premises in which they operate. As well, water efficiency itself is a consideration within the classifications of Premium or A grade space by the Property Council. Such buildings typically attract higher rent when compared with lower graded counterparts.
However, this type of measure involves ongoing consumption of energy and maintenance costs to run, and treatment at the individual building level is not necessarily more efficient compared with that performed at a utility level. Indeed, Dodd said these kinds of plants are usually best suited to new buildings and are often best used in cases like Barangaroo where scale can be delivered through having one plant servicing multiple buildings. Retrofitting in existing buildings can be difficult, he said, as there is a need to ensure no mix of recycled water with that from the mains.
Finally, one of the best investments is metering, which both Morton and Dodd said is crucial in terms of both identifying leakages and problems and communicating with clients about the effectiveness of the building’s water savings strategies and how they can help minimise water consumption.
“Metering is one of the most effective strategies for raising awareness,” Morton said. “When you have proper metering of all your major water uses and have that linked up to your building management system so that for example if there is a leak and all of the sudden the facilities manager can see on the screen that you are using ten times more water in the toilets than you should be, that can trigger alarm and someone can go and fix it.”