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    Credit: Eli Meir Kaplan

By 2020 our homes and communities will consume much less water than today, using the latest technologies to record individual water use and minimize waste. By combining high-efficiency fixtures and appliances, structured plumbing design, weather-based irrigation controls, and graywater reuse systems, residential consumption will drop from 60 gallons per person per day down to 20.

Alejandra lives in a hyper-water-efficient home. As she steps out of the shower, the water leaving the drain trickles into a gray-water holding tank where it mixes with water from the kitchen and bathroom sinks and the clothes washer. After drying herself, she places her towel in a spin dryer that extracts the moisture and delivers it to the graywater tank. When she flushes the toilet, filtered and treated water from the graywater holding tank refills the 0.5-gpf toilet. Later, a subsurface irrigation system delivers a precise amount of treated graywater to plants in her landscape, controlled by soil moisture sensors in the ground and microsensors on the leaves of the plants. An ultra-thin flat screen near the kitchen sink shows her water use for the day and month to date, the amount of graywater in her holding tank, as well as her current energy consumption and solar generation from the panels integrated into her roof tiles. She uses about 20 gallons of potable water per day, and her family of four uses less than 2,500 gallons of water per month for both indoor and outdoor purposes. Welcome to the future.

The good news is, we’re not that far away, at least technologically, from creating Alejandra’s hyper-water-efficient home. The bad news: Some political, economic, and legal barriers must be addressed for us to get there.

We have made progress in reducing our household water use. Research shows that with today’s best-available water-efficient technology people are already using less water; they use on average 35 gallons per capita per day (gpcd) indoors as opposed to the 69.3 gpcd recorded in the standard homes of the past. But to achieve the low water-use levels of Alejandra’s water-efficient home, we need to reduce both indoor and outdoor water use to a level of 20 gpcd, which will require significant changes in the way we plumb and landscape our houses.