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Opinion: What’s the drought solution right under our noses? Graywater

What if we could be using our water twice as efficiently? When you shower, you could also be watering your garden — here’s how

SHARE Opinion: What’s the drought solution right under our noses? Graywater
Receding water from the Great Salt Lake with exposed lake bed.

Record low water levels are seen in the Great Salt Lake from Antelope Island on Friday, July 22, 2022. The megadrought continues, but graywater could be a solution.

Kristin Murphy, Deseret News

March 26, 2020. As the world braced itself for an unknown and rapidly spreading virus, something inspiring happened in the state of Utah: With 100% support, we adopted a radically different and simplified graywater policy.

Graywater includes any water (termed “wastewater”) flowing from your bathtubs, showers, bathroom sinks and washing machines. For the first time in our state’s history, during that quiet spring, this water could legally be used in our yards with a simple gravity-fed branched drain system and a three-way valve. The three-way valve is a small handle that you turn left or right, directing the water either to the sewer/wastewater treatment plant or to your landscape. 

In our state, the word “megadrought” is becoming part of our daily vernacular. The megadrought, visually apparent in our parched Colorado River watershed and in our vanishing Great Salt Lake, is visible from space.

This is why two conflicting words surface when I think about Utah’s water: abundance and squander.

Wait, didn’t I just write “megadrought”? Why “abundance”? The answer lies in two parts: Making better use of our secondary household water through graywater systems, and slowing, spreading and sinking graywater and rainwater into our landscapes through water-harvesting earthworks.

How can you use graywater?

When building our family’s home in Moab, I worked with my local health department (Grand County) to be approved as Utah’s first legal residential graywater system in the state. Now when I shower or do laundry, my graywater feeds two cherry trees, a peach and nectarine tree, along with a series of food producing and pollinator attracting shrubs and plants. As long as I periodically check the outlets and the basins that they flow in to, I never need to add supplemental water.

And I live in Moab where we see an average of only 9.5 inches of rain a year. Moab is also the largest global warming hotspot in North America. We are projected to get hotter and drier. So, although we have the second-lowest water per gallon rate in the country, all climate change and population demand odds are pointing to increased water rates.

Our average household water use in the United States is 138 gallons per household per day. We use an average of 23 gallons for our washing machines and 32 gallons for our showers and bathtubs. These two fixtures alone total 55 gallons per household per day, or 40% of our total average indoor household water use. Fifty-five gallons a day can grow a lot of food, and this doesn’t even account for the water harvesting potential from our bathroom sinks. 

Why not double up on our use of that dwindling water supply? 

Can you use rainwater more efficiently?

Did you know that in just a one-inch rain event, you could harvest 500 gallons of rainwater off a thousand-square-foot roof? Imagine if we began treating rainwater as a valuable resource as opposed to a problem to be sent away as quickly as possible on sloped impervious surfaces.

We can legally harvest up to 2,500 gallons at a time of rain per parcel in our state through either above or below-ground tanks. We can also build water-harvesting earthworks that better slow, spread and sink water into our yards.

Imagine all of this, in combination with a graywater system, and you have both abundance and decreased dependence on our municipal water system amid our megadrought. 

How to harness your graywater

If you would like to install a graywater system in your household, first call your local health department encouraging them to opt-in to administering a graywater program in your county (if they haven’t done so already). A list of our state’s health departments can be found at the Utah Association of Local Health Departments website.

Next, ask them about an onsite wastewater professional who can work with your landscape design to integrate graywater with your other landscaping goals and plant water needs. You can find out much more about graywater systems in Utah at Utah State University’s Graywater Systems fact sheet

Roslynn McCann stands outside in front of trees with orange, yellow and green leaves.

Dr. Roslynn McCann specializes in environmental sustainability at Utah State University.

Roslynn McCann, Ph.D., is a sustainable communities extension specialist in the Department of Environment and Society, College of Natural Resources at Utah State University.