Commercial enterprises are increasingly installing various rainwater harvesting systems for water conservation purposes. Harvesting can also reduce stormwater runoff and fees, and helps solve potable, non-potable, and energy challenges. Commercial property owners are beginning to realize how much stormwater fees are costing them, says Zachary Popkin, program manager for the Energy Coordinating Agency in Philadelphia (via the Forester Network).Rainwater harvesting is an opportunity to collect water from roofs and reuse it, keeping it onsite, which eliminates a huge portion of stormwater runoff, according to David Crawford, president of the American Rainwater Catchment Systems Association (ARCSA). Crawford says the EPA is pushing for more rainwater catchment. Proponents of rainwater harvesting point out that 70% to 80% of water use is non-potable, so it makes no sense to spend money on energy to clean up water and to pump water out and back from centralized municipalities.
Anywhere from 40% to 60% of the cost of water is from the energy used to move the water from one place to another, says Jim Harrington of Georgia-based Rainwater Collection Solutions. "We're literally [...] running out of water that's clean and usable," he says. "You cannot have energy without a lot of water, and you cannot have water without a lot of energy. We talk about energy and read about energy all the time, but we don’t talk about the fact that probably 60% of the water that we use in the United States is used to create energy, for cooling towers and hydroelectric power. You’re talking about billions of gallons a day."
Manufacturing facilities are often water utilities' largest customer. Last fall, Pepsi announced it was reaching its water targets through "a comprehensive approach to water stewardship at the plant level..." This approach includes rainwater harvesting and evaporation technologies.
Rainwater catchment is also a practice that can help property owners achieve LEED status for their buildings. The Birmingham-Shuttlesworth International Airport in Alabama recently received LEED Gold for its terminal, with one of the LEED features in the design being rainwater harvesting that reduces water consumption and discharge into the storm water drainage system, for example (via AL.com).
But problems do exist with rainwater harvesting, one of which is the treatment aspects of it. "There are clean sources of runoff, and there are dirty sources of runoff," says Mike Gregory, a senior water resources engineer with Ontario-based AECOM. "There are some you don't want to touch, while others are perfectly amenable to reuse."
The ARCSA has a list of rainwater harvesting state regulations and technical resources from the US Department of Energy.
