How Tucson Uses Rain and Greywater to Keep Local Gardens Lush

When Brisbane, Australia, suffered a massive drought in 2007, the city passed an ordinance that required new homes to include cisterns to capture rainwater with a minimum capacity of 1,200-gallons. Along with the cisterns came a water gauge. These homes in Brisbane saved 40 percent of their water.

If every home in Brisbane installed such water-harvesting systems, the city wouldn’t need to expand its water resource infrastructure for 100 years, said rainwater harvest and greywater capture guru Brad Lancaster.

“We have all the water we need, even in the desert, if we just know how to capture and use it wisely,” said the Tucson-based Lancaster, who employs similar tactics in his home city. “More rain falls on the hardscapes and roofs in Tucson than the city uses in a year. We just have to capture it.” He says capturing water from roofs, driveways and streets doesn’t take water away from the environment, and it prevents the erosion and flooding that occurs from unnatural concentrations of water flowing off hard surfaces.

“I believe that by harvesting water — and more — we can all begin to transform our households and neighborhoods from being consumers of resources to generators — and even regenerators — of resources,” Lancaster tells readers on his website.

Lack of information stops people from harvesting water

While harvesting rainwater seems logical, Lancaster says lack of information stops people from implementing it. He says it takes a 180-degree shift in thinking for home and business owners to recognize free water is falling on their property and that they can take advantage of it.

The simplest way is to take a shovel and create a simple rain garden for a perennial plant by directing water from a hard surface into a basin that holds that plant. On Lancaster’s own property, which he uses as a laboratory for his ideas, the installations follow the same principle but are more complex.

Lancaster started by practicing in his backyard. Since 1993, when he first became interested in water harvesting, he has developed drains from the main house to two 1,300-gallon cisterns and from the roof of a former one-car garage to two 1,000-gallon cisterns. Overflow from those cisterns, along with direct rainfall and runoff from raised paths and patios, is directed to mulched and vegetated basins in the yard. In times of no rain, he diverts greywater from his washing machine, showers and sinks directly to those same basins. The yard is designed so that water flows into and through a series of basins, percolating into the soil as it flows.

 

 

It is common to cut cores out of curbs to allow water to drain off properties and into gutters. But Lancaster turns the concept around and cuts curb cores to direct street runoff to street-side basins and plantings in the public right-of-way adjoining his property.

Even more dramatic are his strategies for cutting away sections of the curb so water streams into tree basins along the side of the street. Once the basins are full, no water enters the basin but flows in the gutter as it did before the curb was cut.

Lancaster’s journey required wrangling with the city to officially recognize rainwater harvest and greywater capture as legal practices. Once people started to become aware of the potential, political will began to build.

He worked with a candidate running for city council who was ultimately elected. That councilmember spearheaded an ordinance requiring commercial landscapes to provide at least 50 percent of their irrigation water from rainwater. Another ordinance required new homes to include a stubout where greywater could be easily accessed for use on landscapes.

A rainwater harvest manual enhanced knowledge of how to harvest rainwater, and the city established a rebate program providing up to $2,000 for rainwater harvest improvements and $1,000 for utilizing greywater per property.

Tucson has not only made curb cuts legal, but it now requires all new city streets be designed to harvest at least half an inch of rainwater in the adjoining right-of-way.

Lancaster has taken this capture potential even farther.  When Hurricane Odile came through Tucson in September 2014, he diverted the water from the other side of the street to his side. The water he captured made a storm that dropped 1.5 inches of rain the equivalent of a 20-inch event. He describes the process in “Harvesting Rain from a 1,000+ Year Storm Event.”

Changing the greywater regulations pitted advocates against health officials, but it turned out as many as 100,000 people were already illegally using greywater. Instead of enforcing existing law, officials studied those users and found no health risk. A colleague searched the U.S. Centers for Disease Control and Prevention (CDC) data bases, and Lancaster said there was no record in of anyone getting sick from contact with greywater.

While the study found no health risk, it was discovered that some greywater applications performed better than others. The result was the publication of 13 common-sense guidelines and legalization of the use of greywater throughout the state of Arizona, with no inspection, no permit, and no fee – as long as people followed the guidelines.

Greywater systems provided unexpected health benefits

An unexpected health benefit came from greywater capture, which requires homeowners to use the right nontoxic soaps and avoid chlorinated bleach so as not to kill landscapes. The secondary result is healthier residents in homes where greywater is used in conjunction with these less toxic products.

Design is important, too. Placement of plants is important not only for the flow of water, but also for how those plants serve the homeowner.  “If I want to be more strategic and plant one tree, I choose the west side of my home or garden so it shades and cools me at the hottest time of the day,” Lancaster said.

He also advocates lush landscapes and non-native plants requiring more water be kept close to the house and irrigated with greywater and cistern water. Native plants that will survive with little water should be placed on the periphery where they can be irrigated by rainwater passively harvested by rain gardens.

He says his principles will work anywhere, and has consulted not only in the desert but also in places with more water like Georgia, Florida and Tennessee. “Rainwater harvesting works wherever there is a dry climate or dry season; the only thing that changes is the plant palette,” he told us. "Georgia accumulates five times the rain as Tucson, but their plants will be as stressed as ours in a drought.”

Mitigate flooding in wet times and drought in dry times

“No matter where people live, it makes sense to mitigate flooding in the wet times and drought in the dry times,” Lancaster insisted. He makes it clear that one practice is universal for rainwater harvest: Always have an overflow when there is more water than the system can handle.

Finally, developing a sense of community is another hidden benefit of his approach to water management. Previously barren streets now are shaded by native trees, and, because the vegetation creates a cooler environment, more people are out talking, walking and working in their gardens.

In Tucson, neighborhoods are defined by watersheds, creating awareness of where the community’s water comes from and where it goes. After years of trainings, using nonprofits and extension offices to build awareness, and requiring a three-hour course to obtain rebates, Lancaster said people can be found harvesting rainwater in almost any neighborhood in Tucson. And the practice is common knowledge, he told us, whether residents are implementing it or not.

Can capturing rainwater and greywater provide all of a property’s irrigation needs so homeowners don’t have to buy water for landscape use? Lancaster says the answer is “yes” if a plant palette is used whose water needs are in balance with water harvested on-site. This typically results in a 30 to 50 percent reduction in water use and the water bill, he said -- but there is a caveat. “People with high-water consumption landscapes might not be able to provide all their irrigation water needs with harvested water. It depends on the size of landscape and its water demand, along with the extent of the water harvesting system.”

For more information about sustainable rainwater harvesting, visit http://www.harvestingrainwater.com/ or read Brad Lancaster’s book “Rainwater Harvesting for Drylands and Beyond.”

Image credits: 1) Brad Lancaster and Jade Beall Photography; 2) Brad Lancaster and Joe Marshall; 3) Brad Lancaster