by Shane Henson — February 27, 2012—Owners and managers of all types of facilities who are seeking ways to make their buildings more sustainable could benefit from looking at the top of their facilities, not just within them. As America’s expanding urban areas struggle with major water supply shortages and runoff pollution problems, capturing rainwater from rooftops provides a tremendous untapped opportunity to increase water supply and improve water quality, according to a recent report , Capturing Rainwater from Rooftops, published by the Natural Resources Defense Council (NRDC).
In its report, NRDC demonstrates the benefits and potential of rooftop rainwater capture, a “green infrastructure” practice that can be used to retain stormwater runoff on-site, by analyzing ways in which eight diverse U.S. cities could incorporate this simple water collection approach. By comparing annual rainfall totals to rooftop coverage, NRDC determined that opportunities exist in each city to capture hundreds of millions of gallons of rainfall every year for reuse. By doing so, residents of these communities would obtain inexpensive onsite water supplies for non-potable uses, such as yard watering and toilet flushing; reduce runoff pollution; and lower energy costs associated with treating and delivering drinkable-quality water.
Specifically, NRDC’s report illustrates opportunities for capturing, treating and supplying harvested rainwater for non-potable purposes in Atlanta, GA; Austin, TX; Chicago, IL; Denver, CO; Fort Myers, FL; Kansas City, MO; Madison, WI; and Washington, DC. Several success stories also demonstrate the effectiveness of rooftop rainwater capture for new construction in New York, NY, and redeveloped buildings in Santa Monica, CA. The total annual volume of rainwater falling on rooftops in these cities alone, if captured in its entirety, would be enough to meet the water supply needs of at least 21 percent to as much as 75 percent of each city’s population, says the NRDC.
Given this, NRDC encourages cities and states to develop policy options and incentives to encourage more rainwater harvesting. These include:
- Adopt stormwater pollution control standards that require on-site volume retention.
- Adopt standards that require or promote rainwater harvesting and/or water efficiency.
- Review building, health and plumbing codes for barriers to reusing rainwater.
- Provide incentives for decreasing stormwater runoff and promoting water conservation.
- Require use of rainwater harvesting on all public properties.
