Harvesting the sky

Old-timers remember when the Santa Fe River, which cuts through the middle of the city, ran year-round. These days, the river —when it runs at all — is little more than a trickle through a dry, sandy arroyo.

Santa Fe and its 65,000 residents are dangerously close to outgrowing their water supply. The city’s reservoirs on the Santa Fe River above town provide about 40 percent of its water; the rest comes from wells. Meanwhile, the local economy rests heavily on the building industry, which adds some 400 to 800 homes annually. Despite implementing strict water restrictions in the last decade, adding four new city wells and planning for a water diversion project from the Rio Grande River, the city estimates that it could experience water shortages after 2015.

Many Western cities face the bleak combination of rapid growth and a maxed-out water budget. But Santa Fe is working on an innovative solution. If Mayor David Coss gets his way, the city will adopt an unprecedented ordinance requiring all new buildings to install rainwater-harvesting systems. Long championed by green builders, these systems funnel rainfall from rooftops into cisterns, where it’s stored for later use. Some systems purify the captured runoff for drinking and bathing, but most just use it to water lawns and plants. A growing number of buildings use rainwater to flush toilets.

“Rainwater harvesting puts water right back into the system when it is used that way,” says Paul Paryski, who co-wrote the ordinance currently being considered by the city. “It puts it back into the treatment plant. There’s a net increase in water in the system” because rainwater that would otherwise be lost to evaporation is captured and contained.

Using the captured water for irrigation or toilets reserves treated city water for drinking or bathing. An inch of rain falling on a 1,000-square-foot roof can add up to more than 500 gallons of stored water. In Santa Fe, where it rains about 15 inches a year, that amounts to 7,000 gallons per home. If most of the town’s buildings had such systems, almost 2,000 acre feet each year — about 20 percent of the city’s total water use — could be collected.

New Mexico water managers encourage rainwater harvesting. But upstream, in Colorado, using rainwater in this way is illegal, and punishable by a fine of up to $500 per day. “Rainwater harvesting interferes with water rights,” explains Marta Ahrens, public information officer for the Colorado Office of the State Engineer. “Even if that person puts that water back into the groundwater system, the problem is that it is used first. (It) interferes with the priority system.”

John Longworth, chief of the Water Use and Conservation Bureau in the New Mexico Office of the State Engineer, acknowledges that rainwater harvesting holds an ambiguous place in the world of water law. “It’s a tough place to be,” he says. “At this point, we’re using this policy (encouraging rainwater harvesting) as a common-sense approach. In New Mexico, these kinds of activities have been going on for hundreds of years. If you’re not going to be pulling water off of a roof, then you’re pulling it out of a domestic well. It’s six in one, half dozen in another.”

Other cities and states also encourage the practice. Seattle has included systems on some of its municipal buildings, Portland awards grants to fund projects incorporating it and the state of Texas has passed incentives to promote rain harvesting. Even the county surrounding Santa Fe requires new homes over 2,500 square feet to include water harvesting systems. But if the city of Santa Fe adopts the proposed ordinance requiring all new buildings to capture rainwater, it would be the first municipality to pass such a law.

Residents and builders aren’t waiting for the ordinance, however. Many houses already have elaborate catchment systems, and a 600-gallon cistern sitting in a Santa Fe courtyard is not unusual. Even mainstream developers are catching on. At Lena Street Lofts near downtown, a live/work development under construction, rainwater running off the roof will fill a 60,000-gallon cistern, providing about 80 percent of the water needed for toilets. Homes at another development have 600- to 1,200-gallon systems for irrigation. And the Santa Fe Railyard, which includes businesses, municipal buildings and residences, will be linked to a 110,000-gallon rainwater-harvesting system. Nearby, El Corazon, a new condominium community, waters plants with rainwater stored in two 50,000-gallon holding tanks.

“It was the right thing to do,” says Rob Harper, vice president of El Corazon developer Unity Hunt Inc. And it also helps the bottom line. In 2002, the city began requiring developers to either buy water rights and transfer them to the city, or pay to convert standard toilets in homes around the city to the low-flow variety to make up for water they use. El Corazon, built on the site of an old apartment building, elected to conserve water with a combination of low-flow toilets and showerheads combined with rainwater harvesting. Harper explains that they were able to use 20 to 25 percent less water than the old apartment building and were therefore able to avoid paying the toilet-retrofit fee.

But relying too much on the “free” water that falls from the sky could be asking for trouble, says Claudia Borchert, water resource coordinator for the city of Santa Fe. “I’m all for trying to catch rainwater,” she says. “The problem is, people still want to have their green gardens even when it doesn’t rain.” In Santa Fe, the annual 15 inches of precipitation tends to come from quick cloudbursts separated by long periods without rain. “Then it’s hot, and people are watering, and it hasn’t rained in the last three weeks,” Borchert says. “That’s the day you have to plan for, the peak day. And it costs a lot.”

Cristina Opdahl, a former resident of Santa Fe, now lives in a cistern-equipped home in rainy Fayetteville, West Virginia.  This story was funded by a grant from the McCune Charitable Foundation.

• Water
• New Mexico
• Communities
• Colorado