Water Conservation

EVERY DROP COUNTS.

The City of Mercer Island is a member of the Saving Water Partnership, an organization comprised of 19 water utilities in King and Snohomish counties that share a common water source. 

Seattle’s Regional Water System currently serves over 1.6 million people including the City of Mercer Island. Two watershed sources provide the majority of water for the system – the Cedar River Watershed and the Tolt River Watershed. about 70% of the water for the entire system is provided by the Cedar River Watershed, 29% comes from the Tolt River Watershed, and 1% from wells at the Highline Wellfield. This split is mostly dependent on region, so the water supplied to Mercer Island predominantly originates in the Cedar River, although occasionally the City is supplied from the Tolt River. For more information on the City’s Water Utility, click here.

Water demand varies, depending on seasonal weather conditions. Summer and early fall months are typically times when the greatest amount of water is used, primarily for irrigation. The system provides an average of 160 million gallons per day (MGD) for the region, but the goal of the regional water conservation program for 2019-2028 is to keep the total average annual retail water use of the members of the Saving Water Partnership under 110 million gallons a day (MGD) through 2028, despite forecasted population growth, by reducing per capita water use. 

SWP offers tips, tools, and rebates to help people preserve our region’s water for future generations as well as for the other. When we work together to use water wisely, it adds up to make a big difference! Check out the video below for tips on watering your outdoor plants efficiently from one of the experts at SWP:

Thinking about collecting rain water at your home? Learn more about the benefits of using captured rain water for outdoor irrigation, here.

Curious about what to do in the event of a declared Water Shortage? To find information on the City's Water Shortage Contingency Plan, click here.