Skip to main content

Wastewater Becomes a Resource for Growing Food with Help from a Treatment Plant 

By February 13, 2023June 15th, 2023No Comments

More than 4,000 pounds of food were produced at CitySoil Farm in 2022 with the strength of volunteers, students, and the South Treatment Plant

At King County’s CitySoil Farm in Renton, Washington, high school students gather over piles of cards. Each one has a photo of a different type of food: apple, gallon of milk, pound of chocolate. They are tasked with matching each food item to the number of gallons of water it takes to produce that food. Is it 10 gallons, 33 gallons or 1,000 gallons? 

These students are learning about water use as part of a class visit to King County’s CitySoil Farm, a demonstration farm co-located at the South Treatment Plant. As one of five wastewater treatment plants serving King County, the South Treatment Plant takes in waste that goes down the drains of homes and businesses, cleans and disinfects it, and then turns some of it into recycled water and that can be safely used to grow food.  

After a morning touring the treatment plant, students head to the farm where they learn about the valuable resources that can be used from wastewater, and end their day helping with farm service-learning projects. 

CitySoil Farm was started in 2008 as a demonstration site to show the benefits of turning wastewater into valuable resources such as recycled water and biosolids that can be used as fertilizer. After 12 years, it has become a 1.5-acre city farm that not only produces food for the community, but also has outdoor classrooms, an orchard, and multiple learning spaces.  

In addition to school field trips, CitySoil Farm hosts programs and workshops for family and community groups. At a fall event, King County partnered with King Conservation District and Urban League for a family day of exploring worm bins and learning about small-scale composting. A summer adult workshop featured Basilica Bio, which focused on environmental justice and community design.  

Throughout the pandemic service-learning programs and workshops were put on pause, but in 2022 over 500 visitors and volunteers came to the farm and were able to help harvest almost 4,000 pounds of culturally-relevant food that went directly to the White Center Food Bank.  

So just how much water does it take to grow one apple? 33 gallons! At a typical farm, that water would come from a nearby river or drinking water source, but at CitySoil Farm, we’re using recycled water from cleaned wastewater. This keeps water in rivers and lakes for humans and our habitats. 

Want to lend a hand at CitySoil? Learn more and get involved at CitySoil Farm