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


The Official Website of the City of Kent

Report A Spill or Illegal Discharge
Report a spill 

National Pollutant Discharge Elimination System (NPDES)

What is the NPDES Program?

The NPDES permitting program was created through the Federal Clean Water Act, enacted by Congress in 1972.  Its primary goal is to reduce the amount of pollution that reaches streams, lakes, wetlands, oceans, and all other water bodies.


Visit the Environmental Protection Agency and Department of Ecology for more information on the federal and state programs.

To learn more about how to protect water quality in your own back yard visit the  Clean Water Project


What is Stormwater Runoff?

Rainwater collecting on the streetStormwater runoff is rain or snowmelt flowing over the ground. Roofs, driveways, sidewalks, and streets prevent this water from naturally soaking into the ground so it continues moving until it empties into a catch basin, drain, or directly into a stream, lake or the ocean.

As the water travels, it collects chemicals, debris and other pollutants along the way. Our stormwater is not sent to a treatment facility, like sanitary sewer systems. Instead, the stormwater flows through a series of pipes and ditches until it empties into streams, lakes, the Green River, and eventually, the Puget Sound - making pollution prevention even more critical.

Watch this video by King County explaining stormwater runoff and its effects on the area.

What is the City of Kent Doing?

DSCF0030The City is covered under the NPDES Municipal Stormwater Permit (Phase II), which regulates discharges from the City of Kent's stormwater system into streams, lakes and rivers. You can view the Western Washington Phase II Municipal Stormwater Permit for more information. The five major components of the permit that the City is required to focus on are discussed further in the boxes below.

For more information and documents related to Kent's stormwater click here.


We have also prepared the following reports for public review and comment:


Comments or Questions? Contact Shawn Gilbertson by email or phone at 253-856-5560.


Our stormwater pollution prevention education program is geared towards YOU - people who have the potential to affect surface water quality within our city. The goal of the education program is to reduce, and hopefully eliminate, behaviors that contribute to negative impacts on our stormwater system.  

We work with our local schools, neighborhood groups and area businesses to provide education opportunities and awareness. If you are interested in having someone come to your group, please email PublicWorks@kentwa.gov or call (253) 856-5500.


To learn more about what we are doing to keep our lakes, streams, and rivers clean check us out on facebook at The Clean Water Project

What Can You Do to Help?

What Residents Can Do              How Businesses Can Protect the Water

PSSH                                 Report A Spill or Illegal Discharge 


Water quality for kids          

 A Ground Water Education      Help Stormville Prevent Pollution
Click link to play!

 Click to play!  


Animation courtesy of smartwaterways.org








































We welcome and encourage public involvement in developing and implementing our Stormwater Management Program (SWMP). What are some ways that you can get involved?

  • Stay up to date by reading our annual report and program plan, available above.
  • Provide us with your comments or suggestions for the program by PublicWorks@kentwa.gov or calling (253) 856-5500.


If you see any illegal dumping or pollution in our stormwater system, make sure to report it! You can click the icon at the top of this page or call our hotline at (253) 856-5600. If it's an emergency, please call 911. 
















        Kelly_educational_I       Matt_Teaching_I 

Our goal is to identify and eliminate pollution entering the City’s stormwater system through the Illicit Discharge Detection and Elimination (IDDE) program.  An illicit discharge is any release of a non-stormwater substance into our system, like chemicals, garbage or dirt. When we receive reports from residents or coworkers, City staff go out into the field and help with spill response and clean-up. 

A fully documented IDDE program has been developed. This program will include stormwater system mapping and an illicit discharge response program. For more information on why the City of Kent is doing this, you can review Kent City Code 7.14 

Don't forget - if you see a spill or illicit discharge, report it! You can click the icon at the top of this page or call our hotline at (253) 856-5600. If it's an emergency, please call 911.

Oil Bubbles  Oil Slick  Be Spill Ready!             


All construction projects in Kent that disturb one acre of soils or greater are required to develop and submit a Stormwater Pollution Prevention Plan (SWPPP) to the city. The SWPPP includes site specific best management practices (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


The city’s stormwater management standards are stipulated in a combination of city codes, city standards, and adopted standards from other agencies.  More information on these requirements can be found below.


Design & Construction Standards              BMP Activity Sheets         BMP Information Sheets          Surface Water Design Manual    

How to do Stormwater Monitoring: A guide for Construction Sites     

Single Family Home Brochure: Erosion and Sediment Control


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 (Ecology) approves these courses and keeps and updated list of current classes on their website which can be accessed here.


In September and October of 2012, the City of Kent provided CESCL recertification to 40 city staff. 

why is stormwater and water quality affected by development?


Hydrologic Cycle


The water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the earth. In areas that are not developed, most rain and snow fall either infiltrates into the ground or is absorbed by the vegetation. Water that infiltrates into the ground will eventually make its way to surface waters such as wetlands, creeks or rivers through the ground or springs. Water absorbed by vegetation cycles back into the atmosphere through evapotranspiration. The benefits of this process include: pollutant removal, temperature reduction, erosion control, groundwater recharge, flood and draught control, wildlife habitat, recreation and increased property values.


Construction and development affect stormwater through an increase in impervious surface space. Stormwater cannot infiltrate into the ground and falls directly onto surfaces such as roadways, construction sites or industrial sites, collecting various pollutants and discharging directly into surface waters without treatment. Increased impervious surfaces cause the quantity of stormwater runoff to increase as well. Lack of treatment and increased run off can cause many water quality related issues such as pollutant loading, erosion of streambeds and channels, sedimentation in streams, creeks, rivers and other waterbodies, habitat loss and flooding. 


Ecology Issues the New 2010 Construction Stormwater General Permit!

Ecology issued the 2010 Construction Stormwater General Permit on December 1, 2010. The previous permit, the 2005 Construction Stormwater General Permit was set to expire on December 16, 2010. Read about the significant changes that were made to the new permit.


Related websites

Department of Ecology's Stormwater Website

Construction sites in Washington State are required to be covered by a Construction Stormwater General Permit through the Department of Ecology if they are engaged in clearing, grading, and excavating activities that disturb one or more acres and discharge stormwater to surface waters of the state. Smaller sites may also require coverage if they are part of a larger common plan of development that will ultimately disturb one acre or more. Operators of regulated construction sites are required to develop stormwater pollution prevention plans as well as implement sediment, erosion, and pollution prevention control measures.


Ecology's Notice of Application


WA Stormwater Technical Resource Center Website

The Washington Stormwater Technical Resource Center offers stormwater management assistance to Washington NPDES permittees and stormwater managers by providing access to information, training, permit assistance, research and emerging technologies. The Washington Stormwater Technical Resource Center is a joint venture between WSU-Puyallup Research and Extension Center and University of Washington, Tacoma Center for Urban Waters.



Silt Fence pH paper Salmon Soil Pile Pond

The city’s Public Works Operations Utilities Division is responsible for the operations and maintenance (O&M) program for the municipal separate storm sewer system (MS4).  The city works diligently to operate and maintain its 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.

The NPDES Phase II permit requires us to inspect and maintain all city-owned or operated catch basins during the permit term. Additionally, all ponds, vaults, and other stormwater facilities must be maintained on an annual basis. With roughly 18,000 catch basins and hundreds of ponds and vaults, this takes a considerable amount of staff resources to ensure a full-functioning and properly maintained MS4 that will prevent and/or reduce pollution from municipal operations.



 /assets/0/3844/3852/4482/4483/90ae9bd3-0dae-4195-bd06-90eabc96110b.jpg      /assets/0/3844/3852/4482/4483/bd2a81f9-006f-49a1-9cc3-cd021acca154.JPG      wetlands_I