Since September, David Stevenson has been getting the smallest Tucson Water bill possible.

He currently pays the $12.67 monthly service fee and the $14.71 Pima County sewer fee for a grand total of $27.38.

He doesn’t pay for any water use because he isn’t using any water from the city utility.

Stevenson, who designs and sells residential solar systems at Technicians for Sustainability, is completely off the water grid. Instead, he uses what he calls “David’s water.”

His move to utility-free water was gradual, starting in 2008. That’s when the Tucson native put in a 3,000-gallon culvert cistern to collect rain falling onto the roof of his westside home.

With the help of Watershed Management Group, Stevenson learned how to reshape his landscape to passively collect rainwater and how to install gray water systems that capture indoor water for outdoor use.

Once he put in his second rainwater-harvesting cistern and an outdoor shower, it dawned on him that maybe he could live on just the water he collected and reused.

The self-described “tech guy” ran the numbers on how much water he used for showers, drinking, cooking, laundry and other daily activities, not counting plant irrigation.

The math went something like this:

1. By looking at his bill, he determined he used an average of fewer than 350 gallons a month.

2. That equals 4,200 gallons a year.

3. He collects 10,000 gallons of rainwater a year.

“The realization came about a year ago,” Stevenson says. “The moment I did the calculations and saw how possible it was, I immediately wanted to do it.”

Stevenson lives alone and is often not home because of work and his love of outdoor activities. That lifestyle means he already uses a minimum amount of water.

Getting off the grid meant a three-way approach: collecting, reusing and not using water.

COLLECTING

Stevenson turned more than half of the front yard that used to be a circular driveway into a native landscape with ironwood and palo verde trees, milkweed, grasses, desert lavender, jojoba, creosote and a variety of rescued cacti. The Tucson Audubon Society has designated his yard as a wildlife habitat.

Basins, berms and swales in the landscape guide rainwater that falls on his and adjoining properties to those plants, which then don’t need additional irrigation.

Rainwater soaking into the landscape also sustains edible mesquite, wolfberry, pomegranate and quince plants.

A benefit is reducing erosion of Stevenson’s and his adjoining neighbors’ properties, which sit atop the steep bank of a wash.

Water from the cisterns irrigate container beds of winter edibles: cauliflower, broccoli, peas, carrots, lettuce, spinach, kale, chiltepin and serrano pepper.

Stevenson uses a well pump and a five-step filtration system to send harvested rainwater through his faucets, showerheads, dishwasher, washing machine and toilet.

REUSING

Stevenson believes that to save water you need to use it more than once. His gray-water systems push water from the kitchen sink and the washing machine into the yard to irrigate the fruit trees.

A valve allows him to send particularly greasy or tainted water through the sewer system. Otherwise, the nutrient-rich water is piped into a cavity in the ground. That allows food scraps and other beneficial waste in the water to become compost that directly amends the soil for the plants.

Water from his outdoor shower flows to grape vines that provide food as well as a privacy screen and shade for the space behind the house.

After a major bathroom redo, Stevenson will be able to guide water from the shower and toilet into the yard, too.

CUTTING BACK

One big way Stevenson is reducing his water use is with his outdoor composting toilet. Instead of using 1.5 gallons per flush, he’s creating soil amendment to grow his plants.

In another strategy, he keeps his garden beds fallow during hot months because of a summer garden’s high water needs.

Another water saver was moving his water heater closer to the kitchen and bathroom plumbing. Now he doesn’t waste water while waiting for it to get hotter.

Stevenson also tries to do his part to save water resources such as the Colorado River, which feeds Tucson’s thirst through the Central Arizona Project.

By reducing his electricity use with solar panels and small strategies–hanging wet clothes instead of using a dryer, for instance — he’s not using water that’s used to generate electricity.

SHOWING POSSIBILITIES

Stevenson admits that much of the investment he’s made to save water will take decades before showing a financial return.

But his goal isn’t to save money; it’s to show how one could live in a sustainable way.

“Much of what I do is an experiment and setting an example,” he says

He often participates in Watershed Management Group’s home tours and is willing to talk with people about his experiences.

Tucson Water’s residential customers used an average of 80 gallons a day per capita in 2015 for both indoor and outdoor use. Stevenson uses fewer than 12 gallons daily.

He says people can do better at saving water with even a few changes.

“We must set an example for other people who can then see that, yes, it can be done.”

Stevenson switched his water main valve from Tucson Water to David’s water on Aug. 5.

He keeps the service and the ability to turn that valve just in case he’ll need Tucson Water again, but so far he can’t imagine it.

“My expectation is that I’ll never go back to Tucson Water,” he says.

Contact Tucson freelance writer Elena Acoba at acoba@dakotacom.net.