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Stormwater Case Studies Search Results

Case Study Location: Washington: Seattle

Case Study Title: Private Stormwater Facility Maintenance and Inspection

Minimum Control Measure: Post-construction stormwater management in new development and redevelopment

Detention pond in WashingtonThe City of Seattle performs regular inspections of privately owned stormwater facilities in the city and provides information to property owners regarding maintenance.

Location: Washington: Seattle
Annual Rainfall: 37.5 inches
Population: 563,374
Year the Program Started: 1992

Contact Information:

Ellen Stewart
Surface Water Quality Inspector
Seattle Public Utilities (SPU) Exit EPA Site
700 Fifth Ave, Suite 4900
PO Box 34018
Seattle, WA 98104-5004
Phone: (206) 615-0023  


The City of Seattle regularly inspects all privately owned stormwater detention, treatment, and conveyance systems in the city. Under the Seattle Municipal Code (Chapter 22.800), owners of private drainage systems are responsible for maintaining the systems to ensure that they continue to function over the long term.

Property owners are notified with a letter in advance of the inspection and are welcome to accompany the inspector. The facility is inspected for high sediment levels, missing or broken components, and drainage issues. Within 2 weeks of the inspection, a letter is sent to the property owner with a report detailing any problems and explaining how the facility needs to be maintained or repaired. The city also provides a list of drainage contractors and information on best management practices (BMPs) for stormwater drainage systems. In addition, the city provides checklists for how to inspect and maintain many different types of facilities on its Web site.

Stormwater detention basin

Site reinspections occur 60 days after the follow-up letter and report. If compliance is not achieved during that time, a Notice of Violation, which may result in a $300 fine for each day the violation continues, may be issued. The city also coordinates with the property owner to inspect after a drainage contractor has completed any work and before the contractor has been paid to ensure that the job was performed adequately.

The city performs between 200 and 500 inspections per year, depending on priorities and staff constraints. There are approximately 3,000 records in the current database; however, the city does not inspect single-family residences, which account for about 500 sites. Each year 50 to 100 new sites are added to the database.

Additional Materials Related to this Case Study:

Additional Resources and Tools for this Minimum Control Measure

EPA presents this case study as an example to which Phase I and Phase II municipal stormwater programs can refer as they develop their own stormwater programs. Although EPA has reviewed the case studies, they should not be considered officially endorsed by the Agency and are not intended to represent full compliance with EPA’s stormwater Phase II minimum control measures. Each community must decide on the appropriate BMPs necessary to meet its unique permit requirements and local conditions.

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Last updated on June 08, 2007 9:09 AM