TagWater Quality(478)

The Highline Water District's 2022 Consumer Confidence Report details the sources, treatment, and quality testing of drinking water served to customers in the Kent and SeaTac, Washington area. Approximately 75% of the district's water comes from Seattle Public Utilities' Cedar River Watershed, with the remaining 25% drawn from local groundwater wells, all of which are treated and tested for over 200 contaminants before reaching customers. The report confirms that Highline Water District's water meets all state and federal safety standards and is significantly below EPA maximum contaminant levels.

This 2021 annual review by the Washington State Department of Health assesses water quality and shellfish harvesting conditions in Poverty Bay, located near Des Moines and Federal Way. The area holds a mix of Approved, Conditionally Approved, and Prohibited classifications, with most stations meeting bacteriological standards, though Station 701 and Station 720 raised concerns due to elevated fecal coliform levels. Pollution sources such as stormwater runoff and past sanitary sewer overflows continue to be monitored, with ongoing correction efforts supported by Public Health Seattle-King County grant funding.

This 2020 environmental study examines groundwater and soil quality at and around Seattle-Tacoma International Airport from 1997 to 2019, tracking changes in contamination levels and evaluating whether they stem from airport operations, other pollution sources, or stormwater runoff. The report draws on data from the Port of Seattle, surrounding cities, and state environmental agencies to assess the effectiveness of the airport's cleanup efforts and identify any contamination that may have spread beyond airport property. The underlying geology—dense glacial till soils—generally slows the movement of contaminants through the ground in the area.

The Highline Water District 2020 Annual Report details the operations and infrastructure of a public water utility serving the Kent, Washington area, which supplied approximately 2.3 billion gallons of water to nearly 19,000 active meters that year. The report covers water production and quality, preventative maintenance, and capital improvement projects, including the $9.4 million Mansion Hill Reservoir Relocation. It also describes how COVID-19 impacted district operations, leading to modified work schedules, suspended late fees, and delays in several planned infrastructure projects.

The City of Des Moines 2015 Surface Water Comprehensive Plan is a technical planning document prepared by Parametrix engineers in March 2015 for the City of Des Moines, Washington. It addresses the management and infrastructure of the city's surface water systems, covering stormwater and drainage planning for the community. The plan was certified by licensed professional engineers and serves as a long-term guide for surface water improvements in the Des Moines area.

The Washington State Department of Ecology issued this draft addendum to address shortcomings in the NPDES wastewater discharge permit for Seattle-Tacoma International Airport, following a ruling by the Pollution Control Hearings Board. The document outlines required changes to how the Port of Seattle manages contaminated wastewater from aircraft deicing operations, including stricter pollution limits, improved treatment standards, and enhanced water quality monitoring of nearby waterways such as Miller Creek. The revisions focus on reducing harmful biochemical oxygen demand (BOD) discharges into Puget Sound and ensuring the Port implements all available pollution control measures as quickly as possible.

In June 2004, the Washington State Department of Ecology granted a Water Quality Certification to the Port of Seattle for the construction of a third parallel runway at Seattle-Tacoma International Airport (Sea-Tac), along with related projects such as taxiways, navigational aids, and runway safety areas. The certification, designated Order #1996-4-02325 (Amended-2), was updated to reflect a Washington Supreme Court ruling and confirms that the project complies with applicable provisions of the Clean Water Act and state environmental laws. The approval is subject to conditions including compliance with hydraulic project approvals and stormwater permits issued by state agencies.