Stormwater Management Program

APWA Storm GraphicStormwater is true to its name. It’s water from rain, sleet, hail or snow. It’s known as stormwater runoff when it travels along surfaces and enters drains that are part of a pipe system that eventually carries it to our lakes, rivers, creeks and other waterbodies. Stormwater runs off streets, parking lots, driveways, lawns, farms, as well as construction and industrial sites. Before entering drain grates, stormwater gathers pollutants such as chemicals, oils, grease, fertilizers, pesticides, bacteria, sediment, and debris. Runoff may also create large volumes of water that could cause erosion, flooding, and damage to stream and river channels.

The city’s stormwater system includes miles of separate stormwater mains (pipes) and ditches, as well as over 3,100 catch basins. Our Stormwater Management Program is administered by operations and maintenance staff whose mission is to safeguard our waterways like Lake Tye and the Skykomish River.

Protecting Monroe's waterways

Much of how we manage our stormwater system is regulated by state and federal agencies such as the Department of Ecology and Environmental Protection Agency. The City is required to maintain a discharge permit, known as the National Pollutant Discharge Elimination System (NPDES) permit, which requires us to manage and control stormwater runoff so that it does not pollute downstream waters. Our current permit expires in 2024.

Ways we protect Monroe’s waterways through out Stormwater Management Program include:

  • Gather public input on our Annual Stormwater Management Plan, which identifies actions and activities to meet the criteria and requirements of our NPDES permit.
  • Adopting city regulations that support stormwater management for residential and commercial development. 
  • Inspecting the city's stormwater system in its entirety every two years to ensure it is functioning properly.
  • Invest in our stormwater system by installing, maintaining, and repairing our pipes, catch basins, ditch lines, and stormwater ponds.
  • Educate residents, students, and businesses on ways they can prevent pollutants from reaching Monroe's waterbodies. 
  • Engage community volunteer and stewardship groups in activities and events that support stormwater management and water quality.
  • Coordinate with other environmental response agencies should a spill occur with in Monroe city limits.
  • Maintain mapping data of the city's stormwater system to better manage connections between the city and private systems, allowing the city to efficiently respond to an prohibited discharge. 
  • Conduct water quality testing to study and monitor pollutant inputs from the stormwater system to our creeks and Lake Tye.


Chinook Salmon Opens in new window2023 Stormwater Management Program Plan (PDF)

2022 Annual Stormwater Report to WA State Department of Ecology (PDF)

Monroe Municipal Code Chapter 13.32: Stormwater Management Utility

Monroe Municipal Code Chapter 13.34: Illicit Discharge Detection and Elimination

Monroe Municipal Code Chapter 23.40: Storm

WA State Department of Ecology Stormwater Program

United States Environmental Protection Agency - NPDES