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Combined Sewer Overflow Program

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Getting the Word Out about Sewers

Seattle Public Utilities is undertaking an aggressive, $500 million effort to prevent combined sewer overflows and hired PRR to lead the communications and public involvement. With public involvement guidelines and messaging grounded in sound research and best public involvement practices, PRR has prepared Seattle Public Utilities to take on a massive investment in Seattle’s future.

Public Involvement Planning

Conducted public opinion and best practices research to inform the Public Involvement Plan that SPU will tailor for all of its CSO projects.

Community Workshop Facilitation

Planned and led community workshops to address concerns about siting a storage tank facility in the North Henderson basin.

Social Marketing

Fostered a positive public perception of SPU's efforts to reduce CSOs, improve water quality, and spend taxpayer and ratepayer dollars wisely.

Environmental Justice Expertise

Educated ratepayers about the benefits of the CSO program to them.

Combined Sewer Overflow Program


PRR conducted public opinion research to gauge attitudes about, and awareness of, the CSO problem, developed key messages about the CSO program, and created comprehensive public involvement guidelines that will be used for all Seattle Public Utilities’ CSO and green stormwater infrastructure projects. PRR is planning and leading all of the public involvement for the Long Term Control Plan, North Henderson underground facility projects, and upcoming green stormwater infrastructure projects.

Combined Sewer Overflow Program

What's the Story with CSOs?

Although Seattle residents are passionate about their lakes, rivers, and Puget Sound, few people have heard of the CSO reduction program and even fewer understand its benefits. Like many cities, Seattle’s sewer system was designed to carry both sewage and stormwater. Today when it rains, the sewer system runs out of capacity and excess raw sewage and stormwater overflows into Seattle waterways. These are called combined sewer overflows (CSOs).  As part of its CSO reduction plan, Seattle Public Utilities (SPU) is building new storage tanks, increasing the capacity of existing sewer pipes, and working with neighborhoods to implement green solutions—such as rain gardens—to reduce the amount of stormwater entering the system.

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