Memorial Day closure

Most City of Portland offices will be closed Monday, May 27, in observance of Memorial Day.

How to Properly Store Outdoor Materials to Prevent Pollution

Material storage areas exposed to rain and runoff can introduce pollutants into the stormwater system and impact our rivers and streams or soak into the soil to contaminate groundwater. These pollutants can harm fish or remain in the soil for many years. Learn how to prevent pollution.

The City's Role

The federal Clean Water Act requires cities to set rules and regulations to protect the city's sewer and stormwater systems and its watersheds. Environmental Services works with business and industry to meet these requirements.

Storing materials outdoors, including raw materials, intermediate products, by-products, finished products, or waste materials, has the potential to introduce pollutants into the stormwater system if rain is allowed to come into contact with stored materials. Many storm drains in Portland flow directly to a river or stream without treatment. If allowed to reach a river or stream, pollutants in stormwater reduce water quality and can harm fish and other aquatic life.

Rules and Regulations 

Portland City Code 17.39 prohibits the discharge of harmful substances into the stormwater system. The discharge of spilled materials or pollutants stored outside may result in investigations, issuance of penalties, and required corrective actions.  

The  2020 Source Control Manual describes requirements for exterior storage and processing of materials that all new and remodeled areas must meet. The requirements go beyond what is described on this page and include pavement, covering, containment curbs, and sanitary drainage, to keep storage area pollutants contained and prevent mobilization of contaminants from the storage areas. 

Prevent Pollution through Best Management Practices

  • Minimize the inventory of materials stored onsite.
  • Store materials indoors. If indoor storage is not feasible, cover outdoor storage areas with a roof and berm or enclose the storage area to prevent contact with rain and runoff. A storm-resistant tarp should cover the materials if a structural cover is not feasible.
  • Minimize stormwater from flowing on the site by installing berms around storage areas to divert stormwater away from the stored materials or store them off the ground by placing them on racks or pallets.
  • To prevent leaks and spills, store liquids and chemicals undercover in lidded containers within secondary containment.
  • Label all containers (tanks, drums, totes, etc.) to ensure proper use and disposal.
  • Keep outdoor storage containers in good condition.
  • Inspect material storage areas often for container deterioration, leaks, and releases.
  • Install protective barriers such as bollards around tanks to prevent damage from vehicles or material handling equipment.
  • Place spill kits near outdoor material storage areas to enable immediate cleanup of spills.
  • Implement a spill prevention and response plan and post emergency phone numbers throughout the facility.
  • Store waste in covered, labeled, lidded, and leak-proof containers to minimize contact with stormwater and ensure proper disposal.
  • Recycle and properly dispose of waste. Call your local transfer station or waste disposal company for guidance.
  • Train employees in proper material storage.

Failure to implement applicable best management practices may result in the discharge of pollutants which is a violation of Portland City Code. The City will issue enforcement action in the form of a civil penalty if pollutants are discharged from your facility. Appropriate measures to prevent the discharge of pollutants are required.