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King County Executive seeks to formalize long-term pollution control plan


A long-term pollution control plan will meet state and federal standards by 2030 under King County Executive Dow Constantine's proposal to enter into a consent decree with the U.S. Environmental Protection Agency (EPA).


A long-term pollution control plan will meet state and federal standards by 2030 under King County Executive Dow Constantine’s proposal to enter into a consent decree with the U.S Environmental Protection Agency (EPA).

“This agreement affirms King County’s commitment to clean water and a healthy environment while synchronizing with other work in the watershed so we get the best value for ratepayers,” said Executive Constantine.

The Executive asked the King County Council for authority to sign a consent decree that will require King County to control its remaining 14 uncontrolled Combined Sewer Overflow (CSO) outfalls by 2030 to meet federal Clean Water Act requirements.

CSOs occur in older parts of Seattle when small amounts of sewage mixed with stormwater discharge into local water bodies during heavy rains when sewers are full, which prevents backups in homes and businesses. State law already requires King County to limit these overflows to one per year at each outfall by 2030.

The consent decree is a legal settlement with the U.S. Department of Justice and EPA that ensures the County’s current CSO control plan developed to meet the state Department of Ecology’s requirements is implemented and completed. The CSO control plan was recently updated by the King County Council in September.

“It is good news that the consent decree affirms our existing program while allowing future flexibility to consider new information and technology for CSO control,” said Wastewater Treatment Division Director Pam Elardo. “We are fully engaged in meeting our commitments to clean water and look forward to celebrating the completion of this important program by the end of the next decade.”

Since the 1970s, King County has successfully reduced volumes of untreated discharges and uncontrolled CSOs in area waterways by more than 90 percent.

Under the terms negotiated with federal regulators beginning in 2007, the consent decree would enforce a schedule for the County to complete nine CSO control projects to control the remaining 14 uncontrolled CSOs at an estimated cost of $711 million (in 2010 dollars), and impose requirements around documenting program progress.

The consent decree preserves the planning updates approved by the King County Council in September that include expediting Lower Duwamish River area projects and evaluating greater use of Green Stormwater Infrastructure for CSO control. It also gives the County the flexibility to integrate CSO projects with other water quality improvements to attain greater environmental benefits.

The consent decree also assesses a $400,000 penalty for past water quality permit compliance problems which are primarily attributed to the County’s four complex satellite CSO treatment plants in Seattle. Because the plants operate only during severe storms when stormwater fills sewer lines to capacity, operational issues are challenging to diagnose and repair. Corrective measures are in the works or already completed on problems that led to permit compliance problems.

King County’s overall environmental record for its wastewater treatment plants in Seattle and Renton is excellent, with each plant consistently meeting its effluent discharge requirements for more than a decade.

EPA is pursuing a national strategy to put numerous utilities under a consent decree. King County’s utility is one of many across the nation negotiating a consent decree with EPA. These utilities are typically in older, larger cities in the Northeastern, Midwestern and Northwestern part of the country where stormwater is managed by discharging it directly to the sanitary sewer system, which can lead to water quality issues when sewers overflow.

The City of Seattle has also negotiated a consent decree to control combined sewer overflows in its wastewater system. 

The County Council will consider the ordinance allowing King County to enter into a consent decree. With Council approval, the King County Executive could sign the consent decree by the end of 2012.

The United States and State of Washington would then approve and sign the decree, and it will be lodged in federal court. The Department of Justice will then provide a 30-day public comment period.

Additional information about King County’s CSO Control Program is available online at

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