Surface Water Topics

Autumn is upon us and the leaves are falling!
City crews are sweeping our streets, but you can help with our nearly 4,000 street drains!  Fallen leaves, needles, and debris can pile up on our street drains between sweeping, especially when it rains, and cause neighborhood flooding.  The same falling leaves and debris can pile up in your property too.

How can I help?

1.  Check any drainage structures, including your roof gutters, on your property.  Make sure no leaves or debris are blocking and water can flow freely.

2.  Check street and other storm drains near your home or business.  Use a rake to keep them free of debris.  Dispose of the debris with your yard waste.  Sweep debris safely from the sidewalk or street shoulder and do not stand in the street!

3.  Do not rake or blow leaves into the street!  If you see HOA landscaper doing so, please call your HOA and let them know.

4.  Never remove a grate from a street storm drain.  If you see large debris or blockage below a drain grate in the street, contact the City.

5.  Do you have a sump pump in your property, such as a basement or yard drain pump?  Check to make sure it is good working order.  Consider a battery backup in case we lose power.


Under a permit issued by the State Department of Ecology, the City of Mill Creek Surface Water Utility (SWU) manages stormwater runoff in order to:

  • Control storm water runoff and erosion
  • Prevent flooding
  • Protect water quality
  • Rehabilitate stream and drainage corridors to benefit salmon and wildlife habitat

Drainage Facilities
Mill Creek operates and maintains all the drainage facilities located within the public roadways and on city owned property. This consists of 38 different detention and water quality facilities, including ponds, vaults, and detention pipes, nearly 4,000 catch basins, and 50 miles of pipe.

Property owners are responsible to operate and maintain drainage systems located on private property.

Here is a 2017 map of stormwater drains.

SWU Responsibilities
In addition to facility operation and maintenance, the city SWU is responsible to:

  • Detect illicit discharges
  • Enforce development standards
  • Implement new technologies such as low impact development
  • Manage drainage related capital improvement projects
  • Provide educational materials

The annual SWU fees paid by residents and businesses are used for all these activities, as well as general compliance with the conditions of the Ecology NPDES permit.

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Frank Reinart
City Engineer
Phone: 425-921-5745
Report a Spill!