Water is a stretched resource in Austin, Texas, and
rationing is routine. So when Mark and Bridget Flocco discovered that their new suburban home and 2-acre lot gulped 130,000 gallons of water during one summer month, they were appalled. It wasn’t the water bill that bothered them so much as the “insane waste” of pumping drinking water into their yard. “We lived there six months before it became clear that wasn’t the lifestyle we wanted,” says Mark Flocco. “We eventually moved out and started working on one that was more sustainable.”
To put Austin’s residential water use in perspective, roughly 90% is used outside to irrigate landscapes and top off swimming pools, according to Peter Pfeiffer, FAIA, of Barley & Pfeiffer Architects, who designed the couple’s new, nearly net zero–energy house on an 80-foot-by-150-foot city lot. “In the summer, swimming pools alone can lose 5,000 to 10,000 gallons of water a month in evaporation,” he says. “We figured the rainwater catchment had to be three to four times that capacity.”
The home is not quite off the water grid, but it comes close. Austin prohibits potable rainwater systems, and the Floccos use about 2,000 gallons of city water per month inside the house. A 27,000-gallon cistern under the garage supplies the rest. The concrete tank (600 square feet, 8 feet deep, and accessed through a floor hatch) sits next to the basement wine cellar—a potentially risky juxtaposition. To guard against leaks, the cistern has insulated-concrete-form walls covered in concrete sealant, and there is a 2-foot gap and French drain between it and the basement wall. A pump on the cistern bottom sends water into a pressure tank fitted with controls that feed the sprinkler or swimming pool. And a plumbing hookup offers the future option of using the surplus indoors.
Last summer, the Floccos tapped rainwater to replenish the pool and irrigate their vegetable garden and cedar, elm, and oak trees. They dipped into the city supply just once during a drought.
Flocco recently began monitoring the family’s outdoor water consumption. He wrote software for the drip-irrigation system, which runs on his computer server. A weather station monitors the evapotranspiration rate and cues up just enough moisture to make up the amount lost. It also checks to see if it has rained and whether showers are forecast. While Flocco relishes the high-tech setup, he acknowledges its cost burdens: hosing out skimmer baskets after several downpours, pump repairs, and eventually clearing the cistern of sludge. “The overhead for a system this size is too great for someone who doesn’t care that much,” he notes, especially when city hookup is available. “The required gutter shields alone cost more than $20,000. The investment will take a long time to pay back, though water costs may spike. It wasn’t a financial decision.”
Water conservation has its own rewards: reducing the strain on the city’s coffers and the energy used to collect, treat, and distribute it. “Knowing where the water is going changes our behavior too,” Flocco says. “Seeing the numbers, it’s easier to make a difference.”