Inside the Monroe Avenue Stormwater Facility
The facility, located on Monroe Avenue across from the Jimi Hendrix Memorial, is now the largest stormwater infiltration facility in Western Washington.
Stormwater from 260 acres of the Renton Highlands flows into this facility. As the water moves through the system, it passes through several cleaning stages that remove debris, pollutants, and even fine dust.
After treatment, the clean water soaks into the ground, recharges groundwater aquifers, and feeds the Cedar River.
The facility eliminated the need to use an old gravel pit to handle the heavy rain we saw in December 2025. It is situated on 3 acres of land that the city purchased from the property owner to construct this project.
For a more detailed look at the project and how the infiltration facility works, please visit here.
Cleaner water for Renton’s future
Stormwater is rainwater. But when it runs off driveways, sidewalks, and streets, it picks up pollutants along the way. That runoff flows into storm drains and eventually into streams, wetlands, and lakes without treatment. Facilities like this one that treat and infiltrate stormwater help keep our community and our drinking water safe and healthy.
Learn ways you can help keep protect our bodies of water from being polluted here.
Acknowledgements
This project was completed four months ahead of schedule, under budget, and with minimal construction changes. It represents a major step forward in how Renton manages stormwater in a growing urban area.
Thank you to the City of Renton Public Works Department and Otak for your partnership in delivering this breakthrough facility to the Highlands Neighborhood.
Special thanks to the Department of Ecology as well for funding 85% of the project construction cost through Stormwater quality grant funds.
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