Graywater: reusing a precious resource

Utah’s Division of Water Quality is poised to update its policy on graywater systems. The change in code was driven by Utah homeowners who wanted a simpler, less expensive option for re-using water that would otherwise be sent directly to waste-treatment plants. Activists in Moab, particularly, are behind the change.

The term ‘graywater’ refers to all the water that goes down the drain in your home but could, instead, be used for irrigation in gardens and landscaping. That also means it doesn’t have to be processed at a municipal treatment center and can be reabsorbed into the groundwater. The term doesn’t include toilet water or kitchen sink and dishwasher water, which are considered “blackwater” under Utah law as it could contain pathogens and is not considered safe for irrigation.

Utah’s existing graywater code has been in place since the 1990s. Under that code, the type of system required was expensive and required more maintenance than most homeowners were willing to bear.

“That was what we had seen through the years, was people calling and wanting to do graywater and being sort of frustrated by having to put in a fairly expensive system to use a relatively small amount of water,” said John Mackey, manager of the Engineering Section of the Department of Water Quality. “Simply put, the old systems required a holding tank, and generally that leads to pumps being required to deliver the water out to be used,” Mackey said.

Instead of large tanks or mechanical pumps, the new, revised code allows for a second type of system which requires fewer components, less maintenance, and is cheaper and easier to install.

“This system is called a mulch shield, and it allows for gravity service without the tank,” said Mackey. “It’s a lot easier to do, and a lot easier to retrofit into a home or into a single fixture.”

Dr. Roslynn McCann is an Associate Professor of Sustainable Communities at the Utah State University Extension in Moab. In 2015, when she and her husband were building their home in Moab, she took a water harvesting course in New Mexico. As part of the course, the class installed a simple gravity graywater system in an existing home.

“It was really eye-opening to see you could do systems that were simple gravity,” McCann said. “I was like, ‘Why are we not doing this in Utah?’”

She called the local health department and Orion Rogers, the head of the Environmental Health Department at the Southeast Utah Health Department, helped her obtain a permit for an experimental pilot system in her yard.

When her three-way valve is turned to the graywater system, the shower and washing machine in her home empty into three outlets in the front yard. The water seeps into two basins, which are covered in mulch. There, it waters cherry trees, a nectarine tree and lavender shrubs.

The plants are thriving and the system, along with the use of secondary irrigation water, has meant that the family hasn’t had to use municipally-treated water to water their plants at all this year.

In an interview with the Moab Sun News on Dec. 2, McCann demonstrated how healthy the soil in her landscape is by digging her fingers under the mulch and scooping out a handful of black, moist dirt. On her first try, she found a squirming earthworm, as well as some white threads of fungal life, evidence of a thriving soil biome.

Reusing a portion of residential wastewater is not a money-saving device, but it can reduce the burden of manually watering landscaping, and it certainly reduces household consumption of treated water. McCann says there hasn’t been a significant change in their water bill.

“This is part of a bigger issue in our state. Water is so inexpensive,” she said. “Economically, we haven’t noticed a difference, but environmentally? A big difference.”

It may not save a lot of money, and in homes that are built on a concrete slab with the plumbing embedded in the concrete, a retro-fit would be costly. However, installing a system doesn’t have to cost a lot of money.

“If you’re doing it at the point of construction, it’s really inexpensive,” McCann said.

The plumbing consists of commonly available two-inch piping and is simple to add to a standard plumbing system. Other expenses to homeowners would include the labor involved in creating and mulching the catchment basins and the cost of a three-way valve to turn the graywater system on and off.

“It would be amazing if we got to the level at the city or the county where we offer incentives or even free three-way valves to people putting graywater systems in their homes,” said McCann.

Community Rebuilds, a local nonprofit that builds sustainable housing for low-income residents, has been installing simple gravity graywater systems in new homes for years in anticipation of the change in code being approved.

“Community Rebuilds is so excited for this development in graywater code,” said Rikki Epperson, executive director of Community Rebuilds. “We feel that utilizing graywater is one of the lowest hanging fruits in saving energy and conserving valuable resources.”

She added, “Using the water twice takes the demand off of freshwater resources and also puts less stress on our wastewater treatment center. All that, and it waters our trees!”

There’s a reason that a lot of graywater activism has been coming out of Moab.

“The Southeast Health District is probably one of the geographies in the state that is best suited for graywater,” Mackey noted, citing the long growing season and water scarcity of the region. “They’re much more concerned about water conservation.”

He credited McCann’s experimental system with encouraging the code change. The Utah Water Quality Board recently visited McCann’s yard to see the graywater system in action.

“Her demonstration showed that this is a good technology and effective and protective of the public health,” Mackey said. “I think it’s fair to say that they were the driving force that encouraged the state and all the health departments to take a look at the old rule and try to find ways to improve it.”

The code update will soon be opened to a 30-day public comment period. A link to submit a comment will be available on the DWQ website at www.deq.utah.gov/division-water-quality. The comments received will dictate the next step. If there are significant objections, the DWQ may have to revise the update.

However, if there are no comments or the comments are all in favor of the code update as written, then the Water Quality Board will review and likely approve the new code, and set a date within the following few weeks for it to go into effect.

“It’s not always easy to navigate code when you’re trying to do something different,” Mackey said. “We really appreciate the health department and Dr. (McCann) being willing to give it a try on an experimental basis.”

“That’s how technology gets advanced,” he said, “somebody takes a risk and demonstrates that a new idea is good, it’s effective and protective of public health and allows someone to conserve water. So kudos to them.”

Reporting for this story was supported by Molly Marcello of KZMU. Her interview with Roslynn McCann and other local graywater activists can be found at kzmu.org/graywater-in-moab-get-an-earful.

A local experimental system helped prompt a change in state code

“That’s how technology gets advanced—somebody takes a risk, and demonstrates that a new idea is good, it’s effective and protective of public health and allows someone to conserve water.”

– John Mackey