Southwest Environment

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Department of Soil, Water and Environmental Science
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Rainwater harvesting cisterns can save money as well as water

Brad Lancaster checks the hose on one of his cisternsPhoto by Daneb Josue Sanchez
Tucson resident Brad Lancaster checks the hose from one of the painted concrete cisterns that keep his yard green.

By Daneb Josue Sanchez, May 12, 2010

In a land of little rainfall, making the most out of water is not only environmentally sound but good for the pocketbook in the long run.

“With a proper design, a water-harvesting cistern system can provide 30 to 50 percent of all the water needs, and cut homeowners’ water bill by 50 percent,” explained University of Arizona Professor James Riley, who teaches a water-harvesting course in the Department of Soil, Water and Environmental Science. Riley noted he was referring specifically to Tucson, where half of a typical residence’s water goes for irrigation.

A water-harvesting cistern is basically a tank to receive rainwater and store it for later use. Cisterns can be as big as needed for the house and the landscape. They can be made from different materials, such as concrete, galvanized iron, steel, and fiberglass. Ideally, rainwater collects on the roof, moves through the gutters, and drains into the cistern.

Riley said a water-harvesting cistern is a relatively small investment.

“It usually comes to one dollar for every gallon stored,” said Riley. In other words, investing in a 500-gallon storage cistern will cost roughly $500, not counting installation cost. Hiring a contractor could possibly double the investment, he estimated.

One of the only potential problems with water cisterns is mosquitoes. However, installing a screen on the inlet of the cistern will help filter out leaves and other solids while keeping mosquitoes out as well. “The mosquito population can be controlled,” added Riley.

The City of Tucson requires permits for cisterns only if they are taller than 6 feet and more than 10 square feet in area. For more information consult their website.

Tucson residents looking for examples of water harvesting systems can go to Kino Learning Center, 6625 N 1st Ave, and Brichta Elementary School, 2110 W Brichta Drive. Along with his water-harvesting class, Riley helped design and install these systems.

Riley noted that in Tucson there has always been an interest in water conservation, but in recent years, rainwater harvesting has really caught on.

“People are relatively well informed,” Riley said, “and with technology improving and more manufacturers and vendors, water-harvesting systems have become more common.”

In his class, Riley uses Brad Lancaster’s book, “Rainwater Harvesting for Drylands and Beyond: Volume 1.”  Since 1993, Lancaster has been consulting and educating businesses and people focusing on a sustainable approach to the use of the landscape, design, and living – including water harvesting. 

water from the roof empties into a cisternPhoto by Daneb Josue Sanchez
Water from the roof of Brad Lancaster’s Tucson home empties into one cistern before filtering in the next one.

Lancaster’s Tucson home has an interconnected two-cistern system, with the inlet on one of the cisterns and the outlet on the other one. This allows sediment to settle as it comes into the first cistern, resulting in cleaner water coming out of the second cistern.

His cisterns are made of concrete and harvest an average of 100,000 gallons of water a year.  They are located on the west side of his property, where they also serve to provide shade to his garden. By 3 p.m., his garden is already under the shade of the cisterns.

Lancaster doesn’t stop there. He has planted trees for extra shading to reduce cooling expenses. He has dug different basins to store more water on his property.  He has installed various valves to divert his gray water either to the sewer or to the landscape. 

“Whenever I more soil around, I want it to do multiple things,” added Lancaster. “Alone, all these things do little, but when put together they come add up to something juicy.”

In terms of sustainable design and green living, Lancaster said, “it all comes down to one thing – stewardship is the path to abundance. It’s not about having a sustainable house, but living in a sustainable way, where you are more connected to the water and energy you consume, and thus more connected to the community and the land.”


Brad Lancanster’s home page

Link to brief video on James Riley’s water-harvesting course

Tucson Water background on rainwater and gray-water harvesting

City of Tucson Land Use Code regarding Cisterns

How to Build a Water Cistern

Daneb Josue Sanchez, born and raised in Mexico, now is working on a bachelor’s degree in Environmental Science leading to a master’s program in Environmental Engineering at the University of Arizona. He wants to specialize in green design and sustainable living.

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