220 Fourth Avenue South, Kent WA 98032 - (253) 856-5200


The Official Website of the City of Kent

DSCF0023National Pollutant Discharge Elimination System (NPDES)

The National Pollutant Discharge Elimination System is a permit based water quality program implemented under the authority of the Federal Clean Water Act, enacted by Congress in 1972.  The primary goal of NPDES is to reduce the amount of pollution that reaches streams, lakes, wetlands, oceans, and all other water bodies by regulating stormwater runoff. Visit the US Environmental Protection Agency and WA Department of Ecology for more information on the federal and state programs.


Kent complies with NPDES by maintaining a current Western Washington Phase II Municipal Stormwater Permit administered by the Washington State Department of Ecology. The permit has 5 major components that the City is required to focus on and they are described under each tabbed section below.

GRNRAWaterTempThe City strives to inform and connect with citizens on stormwater issues to instill general understanding and appreciation for our vital water resources that will hopefully reduce and eliminate pollution in our city's and region's waterways. The ultimate goal is to affect change through YOU... because only you can change your decisions and behaviors that contribute to negative impacts on water quality.

We work with Kent schools, neighborhood groups, and businesses to provide education opportunities and awareness. If you are interested in having someone talk and meet with you or your group, please email npdes@kentwa.gov or call 253-856-5500. PugetSoundStartsHere

What you can do today!

  • Get more information - you're already here so you're off to a great start!
  • Figure out how stormwater flows onto, around, and off of your property.
  • Learn about ways to prevent pollution from coming into contact with stormwater.
  • Talk to your family, friends, neighbors, coworkers, etc... about stormwater issues such as picking up after pets or storing, using, and disposing of common household products that contain chemicals and hazardous materials.
  • Stay on the lookout for spills and call the Spill Hotline at 253-856-5600 when you see potential for stormwater pollution.

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WeWantToHearFromYouRESIZEforWebThe city welcomes and values citizen engagement in stormwater management and the City's Stormwater Management Program (SWMP) Plan. Public participation is needed in order for us to be successful in protecting and improving the quality of our precious water resources.

Ways that you can get involved and participate:



 PaintCansHuntersGroveBioswaleWe're in this together! 

Everyone can identify and prevent pollution.

Through Illicit Discharge Detection and Elimination (IDDE) we all work together to protect and preserve our natural and built resources.

An illicit discharge is any release of a non-stormwater substance into the stormwater drainage system and/or waterways; substances such as common household cleaners, car fluids and wash water, paint, garbage, dirt, yard and pet waste. 


Through our 24-hour spill hotline (253-856-5600) we receive reports about spills and illicit discharges and/or connections. City staff respond promptly to spill reports in order to prevent pollution from entering stormwater drainage systems and waterways.


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Oil Slick     Don't Drip and Drive Logo     Be Spill Ready! 



ConstructionGoodBMPAll development and construction sites are required to use stormwater best management practices (BMPs).


Examples of BMPs include:

  • Not allowing track out of dirt onto roads
  • Silt fencing to reduce runoff from site
  • Catch basin filter bag inserts to stop sediment from entering the storm system
  • Covering piles of dirt and loose materials
  • Properly storing, using, and disposing of chemicals and all other materials

Click here for the brochure on single family home small projects erosion and sediment control.

Stormwater Pollution Prevention Plan (SWPPP)

Any development or construction site in Kent that disturb one acre of soils or greater are required to develop and submit a Stormwater Pollution Prevention Plan or SWPPP to the city. The SWPPP includes site specific BMPs for reducing or eliminating pollution in stormwater before it leaves the site. The SWPPP’s proposed BMPs must be reviewed prior to permit approval and are required to be continuously inspected during construction in order to reduce erosion potential on the site and to protect water quality.

A complete SWPPP will focus on 12 main elements that have the potential to affect stormwater and water quality. These 12 elements include:

  1. Preserve Vegetation & Mark Clearing Limits
  2. Establish a Construction Access
  3. Control Flow Rates
  4. Install Sediment Controls
  5. Stabilize Soils
  6. Protect Slopes
  7. Protect Drain Inlets
  8. Stabilize Channels and Outlets
  9. Control Pollutants
  10. Control De-Watering
  11. Maintain BMPs
  12. Manage the Project

In addition to developing and implementing a SWPPP, all construction sites disturbing greater than one acre of soil are also required to conduct periodic inspections of their site to verify that the proposed BMPs are adequately protecting the site from erosion and sediment control issues. It is required that every construction site has a Certified Erosion and Sediment Control Lead (CESCL) who conducts the required inspections. A CESCL is a person who has current certification through an approved erosion and sediment control training program. The Washington State Department of Ecology approves these courses and keeps and updated list of current classes on their website.


010 Utilities Storm Drainage - Mark traing Jason 2 Kent Public Works Department is responsible for the operations and maintenance of the municipal separate storm sewer system (MS4).  

Staff work diligently to operate and maintain Kent's MS4 for efficient conveyance, storage, and, in some cases, treatment of stormwater before it is discharged to surface or ground waters, to reduce localized flooding, decrease instances of erosion, and allow treatment processes to function properly.  

Your drainage utility fee helps pay for inspection, operation, and maintenance of all publicly owned and/or operated stormwater conveyance and facilities including:  Luke_Leaves WEB RESIZE

  • 18,000+ catch basins 
  • 350+ detention/retention ponds and bio-retention swales
  • 50 stormwater flow control and treatment facilities (vaults and filter vaults)
  • 300+ miles of pipes and roadside ditches
  • Stormwater pump stations
  • Dams
  • Culverts and channels
  • Creeks
  • Wetlands
  • Lakes
  • Green River in Kent

It takes a considerable amount of time and staff resources to accomplish inspections and maintenance to ensure a full-functioning MS4. To view the annual storm division work plan go to: Operations Work Plans.

Examples of operations and maintenance activities: 

  • Respond to and clean up spills and illicit discharges
  • Clear debris from roadside ditches, inlets, outlets, and culverts to prevent and alleviate flooding
  • Inspect catch basins, flow control, and treatment facilities
  • Install and restore structures, pipes, culverts, ditches, etc...
  • Remove sediment and debris from structures, pipes, culverts, ditches, etc...
  • Manage vegetation in ponds, bio-retention swales, wetlands, ditches, etc...

 Flood Response  Clearing Outlet  Spill Response Clearing Leaves from Catch Basin Grate  Clearing Debris from Culvert Inlet  Spill Cleanup Removing Debris from Culvert Inlet  Remioving Leaves from roadside  Removing Sediment from Catch Basin Removing Debris from Inlet  Catch Basin and Pipeline Cleaning  Catch Basin Cleaning Spill Response  Replcing a Curb and Gutter  Storm Line Install BMP_ditch  ClearingFishScreenAtBoeing  Sawcut for storm system repair Ditch Maintenance  Replacing catch basin lid  Roadside Veg Management Storm pipe repair  Pond Vegetation Management  Planting Veg Management CB Repair Tony Mann  Vault_Inspection  Pond Veg Maintenance Weed Wack



Report A Spill

Report spills immediately.

Every second counts!

Call 253.856.5600 



Find out about stormwater management in Kent and how you can help.


Homeowners Protecting Water

How residents can help protect water quality


Businesses Protecting Water

How businesses can help protect water quality