Source Control Pollution Prevention for Businesses

The Stormwater Source Control is a new program Cowlitz County is implementing to stop pollution before it enters the Cowlitz, Coweeman and Columbia Rivers.  As a Western Washington Phase II Municipal Stormwater Permit holder, Cowlitz County is mandated to conduct source control inspections of identified businesses. Starting  in 2023, county staff will begin conducting site inspections as required by the permit as well as with the goal of keeping potential pollutants from contaminating stormwater and local waterways.

Purpose of Stormwater Source Control

Stormwater Source Control aims to address non-point source pollutants that originate from business / business site activities such as fertilizers, oil, grease, washwater, etc. This polluted stormwater then collects  from combined runoff from commercial, industrial, or other activities and discharges to receiving waterways and eventually into Cowlitz, Coweeman and Columbia Rivers.

Polluted stormwater has been shown to have negative impacts on all species that depend on healthy water quality.  The goal of source control inspections is to educate businesses, public and private property owners about methods to prevent stormwater pollution.

Information collected during the inspection will be used to generate a tailored report for your site outlining actions, if needed, to be taken to keep potential pollutants at their source.  Inspections aim to help businesses implement best management practices (BMPs) to reduce stormwater pollution for a healthier environment The Source Control inspector will provide information about BMPs that have been specifically designed to address problem areas.  BMPs can be simple changes to operational practices such as closing the lid on your dumpster or more involved structural changes such as building spill containment for outdoor chemical storage areas.

 Inspectors will work with businesses to reach compliance by addressing areas of improvement. If inspectors find facilities failed to meet Stormwater Source Control program requirements, a corrective action letter will be sent.

County created and adopted County Code that requires businesses, property owners and publicly owned facilities to comply with stormwater source control regulations. This code also includes provisions for enforcement, including civil and criminal penalties for non-compliance. However, it is the County's intention and desire to work cooperatively with businesses and property owners to provide education and technical assistance for successful implementation of source control requirements.

What does this program entail? 

The Phase II Municipal Stormwater Permit requires that municipalities inspect a minimum of 20% of their identified businesses annually.  Businesses whose activities pose a higher risk of releasing pollutants to the environment and those businesses who have a change in site conditions or activities will be inspected more frequently.  In addition to the Source Control Program inspections, the city will continue to inspect all illicit discharges and complaints as required by Permit. 

Inspection Schedule

County staff will contact you approximately two weeks ahead of time to schedule an inspection. At that time, the inspector will also verify contact information, collect information about your business, chemicals stored on your site etc., as well as confirm the required personal protective equipment needed for accessing your site.

What to Expect During an Inspection

Generally, inspections should be completed in 30-60 minutes. However, larger facilities may require additional time to complete the inspection. During a typical inspection, inspectors will do the following:

  • Observe the facility during normal business operations.
  • Visit loading sites, storage, and process areas.
  • Check site storm drains for signs of pollution.
  • Make recommendations to reach compliance.
  • On inspection day, staff will ask to see spill plans as well as request other documents such as any site plans/as built drawings or other permitting documents. Additionally, staff will ask to survey your entire premises including both the interior and exterior of your business with emphasis on outdoor activities that could come into contact with stormwater.


To help businesses meet Stormwater Source Control program requirements, here are a few resources:

Educational Brochures

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Municipal Stormwater Source Control Business Inspection -Typical Questions

Business Contact Info Form