Nationwide, the tug of war over diminishing water resources provokes challenging questions about how we should prioritize water use among competing interests like agriculture, urban consumption and the environment. These questions grow increasingly difficult as more communities realize they don't have enough water to go around.
Many communities believe that, because they've already witnessed significant reductions in water use, they now need to start building their supplies only through options like reservoirs or desalination. In some cases they're right, but in most cases they're very wrong. The fact is, we're not finished with efficiency and conservation. Outdoor water use is the next frontier.
It's true that we've made great strides in conservation. Average annual indoor household water use has dropped by 22 percent since 1999, thanks largely to the use of high-efficiency toilets and showerheads as well as more water-efficient clothes washers and other appliances. But outdoor residential water use represents a largely untapped and immensely promising source of water savings.
Even a small reduction in water use on home landscapes can have a significant impact on community water supplies. Landscape irrigation is estimated to account for almost one-third of residential water use -- nearly nine billion gallons a day. And as much as half of the water used outdoors is wasted due to evaporation, inefficient equipment and overwatering.
Driven by persistent drought conditions, communities throughout North America have already implemented programs to incentivize and accelerate water-efficient changes to urban landscapes. From Sacramento, Calif., to Austin, Texas, they have tested diverse approaches, including free or subsidized efficient-irrigation technologies: incentives and design assistance to help homeowners replace unneeded, water-intensive turf with more climate-appropriate plants; and educational campaigns to increase awareness of outdoor water use.
A new research effort from the Alliance for Water Efficiency -- the most comprehensive to date -- shows that these programs and policies make a real difference for a community's water supply portfolio, regardless of the type of program. Across programs analyzed, the average water-use savings for single-family customers ranged from 7 percent up to 39 percent.
A San Diego County Water Authority initiative illustrates how effective these efforts can be. The agency's Sustainable Landscapes Program helps homeowners achieve multiple benefits, from efficient water use to stormwater management. It holds "Landscape Makeover" classes, offers technical assistance, distributes compost and mulch, and provides rebates for smart irrigation technology. The average participant has saved 42,000 gallons annually. That's enough water to meet the needs of a four-person household for nearly 100 days.
These are especially high-value water savings that reduce the peak demand on the water system, and therefore can help drive down long-term utility and customer costs. Even better, these programs reap increasing returns. Homeowners who invest in a sustainable landscape continue to do so and build water savings over time. This growing reservoir of conserved water makes their communities more resilient to potential water shortages and able to accommodate growth, while also boosting watershed health.
Local decision-makers may wonder if residents are truly ready to alter their landscapes. Our survey of more than 3,000 North American homeowners indicates that the time is ripe to promote a new landscape ideal.
While beauty and appearance was the most important aspect of their landscapes, nearly half of respondents also wanted their landscapes to be water-conscious. And contrary to popular belief, for most people a beautiful outdoor space doesn't always conjure up visions of endless expanses of thirsty grass. More homeowners desired trees, flowers and functional spaces for entertaining.
Sustainable landscapes come in many shapes and sizes, depending on the region and climate. They may feature colorful native plants, increasingly smart irrigation technologies triggered by a phone app to apply just the right amount of water, or new drought-tolerant turf grass species that use 30 percent less water than conventional varieties. What these landscapes have in common is that they help homeowners enjoy their outdoor spaces while also supporting important community water objectives.
Decision-makers at the community, regional and state levels are already facing hard choices about how to distribute shrinking water resources across equally important needs. Outdoor water-use efficiency provides a mostly untapped strategy to stretch existing supplies without the need to deprive farmers and businesses of water or build more expensive infrastructure. Achieving that goal requires recognizing the value of sustainable landscapes, investing in programs that work and starting a conversation within our communities about the water source right outside our windows.
