Water is delivered to Mercer Island by Seattle Public Utilities via 16" and 24" water supply lines. The water is stored in two 4-million gallon reservoirs for domestic use and fire protection. Water is distributed through 4" to 30" waterlines and is delivered to customers through approx. 7,300 water meters.
Water quality testing and monitoring is performed as required by the Environmental Protection Agency Safe Water Drinking Act.
Watersheds: The Source of Our Water
The regionís fresh water supply water comes primarily from two sources: the Cedar River Watershed and the Tolt River Watershed, both located in eastern King County. The watersheds are large, uninhabited land areas that gather and store rain and snowmelt. Year-round, 26 cities and water districts rely on a limited supply of stored water from these two sources to meet most of the daily needs of business, government, institutions and 1.3 million people in our region. In addition to providing clean, clear, reliable drinking water, the watersheds also provide habitat for fish and wildlife.
Water Quality Report 2012 - NEW
The City of Mercer Island is pleased to tell you that our compliance with all state and federal drinking water laws remains exemplary. We are committed to delivering the best quality drinking water. To that end, we remain vigilant in meeting the challenges of water system protection, water conservation and community education. To view the report, please click here.
Water Standard Details
Click here to view each section of the most current version of the Water Standard Details.
Click here to view a list of local laboratories to contact for residential water testing.
Water Conservation Tips: How to be Waterwise
Water conservation is important for our region, our environment, future generations and your pocketbook. Click here to see how to be waterwise.
Just how much water does Mercer Island use anyway?
Historically, Mercer Island has been one of our region's biggest water users during the summer "demand" season. A variety of conservation efforts funded through the Water Utility are targeting this seasonal peak in consumption. Click here to see how much water the Island uses each month.
Water System Plan
The purpose of the Water System Plan (WSP) is to examine the existing system and its operation, analyze system hydraulics, study current and projected future conditions by computer modeling and develop a plan to meet the Cityís water system needs to the year 2028 and beyond. The drafted 2008 WSP has been reviewed and commented on by the Department of Health (DOH) and the Seattle Public Utilities (SPU). Responses to both agencies were addressed in response letters provided by the City. Revisions to various subjects and areas of the draft 2008 WSP were made in accordance to the agencies' review comments. The final 2008 WSP was adopted by the City Council on July 7, 2008. A copy of the 2008 Water System Plan is available at City Hall.
Central Puget Sound Water Suppliers Forum
Click here to learn about the Forum's purpose, members and most commonly asked questions.
The City developed the emergency well to supply Island residents with water for an extended period of time without significant assistance from outside during an emergency. Click here for more information.
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