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King County CSOs --
Public Notification and Posting

CSO Overview Map

North Seattle CSOs

South Seattle CSOs

West Seattle CSOs

CSO Warning Sign
CSO Warning Sign
(posted near CSO outfalls)


About this map

The CSO status information on this page is updated every 10 minutes.

Move your cursor over the map and click to view detail maps of North, South and West Seattle CSOs.

Data displayed on this map has not been reviewed by King County. King County reviews all CSO data on a regular basis and determines if an overflow truly occurred at a location.

Maintenance or equipment malfunction may show a false CSO discharge. Official data is available in King County's Annual CSO reporting to the Department of Ecology.

This map does not show information for the 90 City of Seattle CSOs.


The purpose of this Web page is to give the public the opportunity to make decisions about the use of waterways during heavy rains. CSOs usually discharge in the winter between October and May. During the CSO discharge and for 48 hours following the discharge, water users near the CSO locations are at risk from exposure to bacteria in the water.

In 1997, King County worked jointly with the City of Seattle, Seattle-King County Health Department, and the Department of Ecology to develop a combined sewer overflow (CSO) public notification program consisting of:

  • warning signs near CSO outfalls
  • CSO information line (206-205-1151) and
  • Web site (maintained by Public Health) to answer health concerns about CSOs

Real-time status now available

Ten years later with new technology and equipment installed at King County's wastewater facilities, real-time information is now available. At the request of environmental groups and the Department of Ecology, King County is now able to provide this information to the public.

Below is a map showing the 38 CSOs that are operated by King County. Thirty two of the locations have real-time information available because they are part of the computerized system that controls the wastewater system. The other six are monitored, but the information is not monitored in real time. Data from these locations is manually entered into the system by staff.

Annual reporting of CSO discharges (number of times and the volume of the discharge) is available in King County's Annual CSO reporting to the Department of Ecology.

King County Combined Sewer Overflow Locations
map legend

Requesting Feedback

This is a pilot program that we are continually trying to improve and make useful. Please let us know how this is working for you and any comments or suggestions you may have.

For more information concerning water quality see these sites:

 

More on CSOs:
Introduction
Reduction and Cost
The CSO Program
Being a Good Neighbor
Library
Glossary of Terms


If you have questions about the CSO Control Program, contact Karen Huber.

Department of Natural Resources and Parks
Wastewater Treatment Division
201 S. Jackson St., Suite 512
Seattle, WA 98104-3855
Phone: 206-684-1246
Fax: 206-684-2057

Updated: May 16, 2008
 

 

Related Information:
Seattle-King County Public Health CSO Public Notification Program

Duwamish Waterway Programs

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The details.

Click to view detail map of North Seattle CSOs, Real-Time Status Click to view detail map of West Seattle CSOs, Real-Time Status Click to view detail map of South Seattle CSOs, Real-Time Status