Rain and snowmelt that collects on impervious surfaces like roofs, roads and parking areas, becomes stormwater runoff. Runoff that reaches our rivers or infiltrates into our groundwater often carries harmful pollutants. Heavy metals, lawn and garden chemicals, animal waste, sediment, petroleum products, and trash are common pollutants found in stormwater. In fact, urban runoff is responsible for more than 60% of the water pollution in Washington State!

Even though Pasco only receives an average of 8 inches of rainfall annually, the pollutant load here can actually be even greater than in cities that receive much more rainfall. That’s because the pollutants have a longer time to collect and concentrate on impervious surfaces between our infrequent storm events.

To ensure the health and safety of our citizens and our rivers, the City of Pasco operates a Municipal Separate Storm Sewer System (MS4) under a Phase II Eastern Washington Stormwater Permit (Permit (PDF)) issued by the state of Washington.  In accordance with the Permit, the City developed the 2022 Stormwater Management Program Plan (SWMPP) to inform the public of actions and activities that are planned during the upcoming annual reporting cycle of the MS4 Permit.

The SWMPP is updated annually and submitted to Ecology with the MS4 Annual Report in accordance with Permit Requirements S9.  In general, the SWMPP is designed to reduce the discharge of pollutants from the City's regulated MS4 to the Maximum Extent Practicable (MEP), satisfy the state requirement under RCW 90.48 to apply All Known, Available, and Reasonable methods of prevention, control, and Treatment (AKART) prior to discharge, and to protect water quality.

On March 24, 2023, a draft 2023 SWMPP was made available on the City's website and open to public comment through April 30, 2023. Here you can find the DRAFT 2023 Stormwater Management Program Plan  

The City’s annual report (PDF) documents the steps we’ve taken to comply with the conditions of the Permit.

The good news is that we can all do something to help to keep our stormwater clean!

If you are having problems with road drainage, blocked storm drains, property or basement flooding, or to report illicit discharges to the City’s stormwater system please call the STORMWATER HOTLINE at 509-543-5777

Construction Pollution Prevention Free Webinars 

The Washington Stormwater Center and the City of Vancouver invite contractors and engineers/designers to a series of 4 webinars that provide guidance in preventing pollutant discharge during construction. Click here to register
Webinars: see attach fliers for more information
Prevention Beats Pollution March 25, 2022, 3-4 PM
Clean Water is Good Business March 29, 2022, 9-10 AM
The Devil’s in the Details: Setting Up For success April 20, 2022, 12-1 PM
How to Design and Keep Your Construction Project in Compliance April 26, 2022, 12-1 PM

WSC Construction Training Video Series

The Washington Stormwater Center, in collaboration with CWT, LLC. (CWT) is pleased to provide this series of videos for BMPs used in the construction industry for smaller projects and municipal maintenance activities. The course provides instruction on the variety of BMPs available to the construction industry and how they can be used to control erosion. Here's a link to the playlist of 8 videos

Recording of Intersectional Environmentalism – Emily Pinckney Approaches including the HEAL Act and the EJ Task Force. 

Farmers' Market Webinar Information: 

Free Webinars for Event Vendors Registration Info
Free Webinar Registration Info 


City of Pasco Standards & Specifications

City of Pasco Comprehensive Stormwater Plan (2016)

Stormwater Management Manual for Eastern Washignton

Eastern Washington Low Impact Development (LID) Guidance Manual