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Using rain to save the desert

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Phoenix skyline and cactus

Phoenix midtown skyline with a Saguaro Cactus and other desert scenery in the foreground. / Getty Images

TUCSON (KVOA) -- Last month, the Bureau of Reclamation declared the Colorado River's first shortage in CAP water deliveries, with the first cuts in water use going into effect in January. With more water shortages looming this is forcing desert dwellers to turn to alternate supplies of water.

Rain water harvesting is not a new concept but local governments, utilities and individuals are increasingly turning to rain to save the desert.

"We have nine feet, four and a quarter inches in the cistern right now. And that's 216 gallons an inch for those nine feet," said retired biologist, Jay Cole.

Cole uses a long, wooden stick to measure the amount of water in his 26,000 gallon below ground cistern. Cole and his wife, Carol Townsend, built their retirement home in the Tucson Mountains 18 years ago. They incorporated a rain water harvesting system into the blueprints. They also dug a well, not sure how their rainwater harvesting experiment would go.

"And it's turned out that the rainwater system was the best thing we could do because it's such a high quality," Cole said. "And it does provide all the water we need for all of our indoors household uses of water and it maintains our swimming pool and on a good year we can maintain a couple of vegetable plots."

They use well water for their outdoor plants.

Rain water is captured on the metal roof and transported to the cistern. Water was abundant this summer with a record breaking monsoon.

"The tank overflowed this year, we had 11.4 inches of rain out here. the tank was about down to 2 feet out of 10 feet and in July it was overflowing," said Cole.

In the 18 years they have lived in their westside home, they said last year's monsoon was the worst.

"We changed our normal water usage from approximately 90 gallons a day for two people in the house, 45 per person, which is our year around average, to only 74 gallons of water per day, by just changing our behavior inside the house," Cole said.

David Rabb has a similar sized above ground system.

"We drink it, we irrigate with it, we flush the toilets with it, it's everything," Rabb said.

He just installed his rainwater harvest system in December, he said he hasn't used city water since.

"The expectation is our water heater should last longer, our coffee maker should last longer, all of our fixtures should last longer because they won't get corroded like the do with normal Tucson water," he said.

Rabb said his tank also filled up quickly with the arrival of the monsoon.

"We have the roof , it's just a little under 5000 square feet, you get a little over .6 gallons of roof per inch of rain so an inch of rain puts about 3000 gallons in here," Rabb said.

Tucson Water offers up to $2000 in rebates for installing rainwater harvesting systems.

"Rain water and storm water is a huge untapped water resource for our community," said James MacAdam, Superintendent of Public Information and Conservation with Tucson Water.

The utility's conservation report found the rebate program saved more than 52 million gallons of water from 2018 to 2019. To qualify for the rebate, residents must take a class on rainwater harvest. Rainwater harvesting is divided into two categories, active and passive.

"If you don't have the money right away to invest in an active system a passive system is like digging a shallow depression, and finding out where the low points on your property are and purposefully slowing don't the water there," said Parker Filer, Assistant Agent of Horticulture with UA/Pima County Cooperative Extension.

Water conservation both Rabb and Cole to install rainwater harvesting systems.

"For me, it's about the satisfaction of doing the right thing," Rabb said.

Cole said he and his wife approached the project like an experiment. "The beauty of all this is we collect all the water we need right here off our roof, no bigger footprint than the roof of the house and we don't use any electricity to collect 26,000 gallons. It's just all gravity feed from the roof into the cistern," he said.

Once the rainwater is harvested, it goes through filters. Both Rabb and Cole use charcoal and UV light. The Cole's had their water quality tested and the results are impressive. The EPA allows for 2 nanograms of Mercury per liter, but the lab couldn't detect any mercury in the Cole's water. They also had extremely low levels of arsenic and lead.

Both, Rabb and Cole rave about how good their water is.

"Did I tell you how great the water is? The water tastes amazing," Rabb said.

"The water quality though is outstanding, by the time we have our drinking water ready to go we only have 4 parts per million of dissolved solids in the water can hardly be anymore pure than that and it tastes wonderful," Cole said.

If you are interested in learning more about Tucson Water's rainwater harvest rebate, click here. You can sign up for rainwater harvest classes here.

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