In the midst of its worst drought in more than a century—rainfall in some regions is half what it should be—Australia is dealing with a water crisis of unprecedented proportion. Many areas of the country are operating under severe water restrictions as the government attempts to avert a disaster. In response, architects and builders throughout Australia are incorporating advanced water-efficient measures that U.S. water experts point to as practical solutions for our own looming crisis.
The desperate conditions in Australia prompted New South Wales custom builder Joe Mercieca to look beyond traditional water conservation tools in planning his own new home four years ago, and he resolved to push the envelope on how self sufficient the house could be. But Mercieca soon found that the small-scale water reclamation products and technologies he needed were not readily available. “We knew what we wanted to achieve,” he says, “but there was no one out there who could help us do it.”
So Joe and his wife, Merylese, and local architect Ross Young studied already-available commercial systems and found that many of them could be adapted for residential use. They were determined to build a user-friendly and extremely water-conserving house that could be replicated using the systems they’d selected. The resulting home won last year’s GreenSmart Award for Water Efficiency from the Australian Housing Industry Association.
“We made very sure we were putting the right technology into the house so it would be fairly cost effective, and that it would work,” Mercieca says, “because a lot of what we were thinking of doing was just hearsay as to whether it would work on a domestic scale.”
The house in the Blue Mountains bush country, completed last April, captures and treats 100% of its own water, making use of it twice inside the house before employing it for irrigation. The whole-house water processing system cost $54,000 (about $55,300 in U.S. dollars).
For emergency purposes, the house is tied in to the municipal water system but Mercieca doesn’t foresee needing it: The reservoir tanks hold a 250-day supply of water so that even with no rainfall his family of five could live in the home for more than six months without tapping into the town’s water supply.
Rainwater collects on the 3,700-square-foot home’s four slanted and curved corrugated metal roofs and flows into three tanks, where it is screened and gravity-fed into a 32,000-liter main tank at the rear of the house. In total, the four tanks are capable of holding 90,000 liters.
The water in the main tank is pressurized and pumped into the house for showers, cooking, drinking, and dish washing. To bring it to drinking water standards, it is cartridge particle- and UV-filtered before entering the house.
A compact greywater system re-treats wastewater from this first round of use and prepares it for washing laundry or cars; toilet flushing; and above-ground garden watering. A 3,000-liter polyethylene tank at the back of the house holds the treated greywater.
Once it is utilized a second time, the water diverts into the blackwater system’s 1,500-liter underground tank, which is set off from the house in the backyard. After undergoing a sanitizing process, the wastewater irrigates the site’s 5 acres of lawns and gardens. The house has no access to the municipal sewer system.
In addition to collecting, treating, and recycling water, the home is miserly in how much it uses, with dual-flush toilets, low-flow faucets and showerheads, and an ultra-efficient washing machine and dishwasher. The fixtures are certified to a minimum 4-star rating out of 6 in the country’s Water Efficient Labelling and Standards (WELS) initiative, a joint program of federal, state, and local governments.
A 26-year veteran of the Australian construction industry, Mercieca is known for building environmentally sound homes that are responsive to their natural surroundings while taking into account clients’ needs and style preferences. His own home includes high-performance features such as a 4.2-kW PV system that generates nearly 100% of the home’s electricity, in-floor hydronic heat, and a roof-mounted evacuated-tube water heating system. The dwelling is also ultra-fireproof—thanks to its concrete block foundation and non-flammable metal siding—a necessity due to the home’s location in a bushfire-prone area.
Four years since Mercieca first dove into on-site water collection and reclamation, products are much easier to come by, he says, as drought-weary Australians’ interest in the technology soars. The real proof of his home’s self reliance came last Christmas when houseguests upped the home’s capacity from the usual five people to 11 people, for several days.