Seattle Public Utilities supplies water to over 1.3 million people in King County and southwest Snohomish County. For most of Seattle’s history, water consumption has increased along with its population. However, that link was broken around 1990 when consumption reached its highest level of about 170 million gallons per day (mgd).
Since then, water consumption has steadily declined due to various forms of conservation despite continued population growth. Seattle and its suburban customers now use just over 120 mgd. That’s about as much water as Seattle and the surrounding suburbs were using in the 1950s with only half the population.
- A drought in 1992 led to mandatory water use restrictions and a sharp (but temporary) drop in summertime water consumption.
- At the same time, Seattle launched an aggressive conservation program and drastically reduced the amount of water that was lost through in-city reservoir leaks and overflows.
- In 1993, a new state plumbing code established efficiency standards for all new toilets, shower heads, and faucet aerators.
- Finally, a wave of conservation programs began in 2000. The goal of these programs is to reduce water consumption per person by 1% every year for 10 years.
As a result, water consumption plummeted even as the population continued to grow. Since 1990’s peak water use, Seattle system water consumption has declined by about 29% (50 mgd) while population has increased 20%. On a per person basis, water consumption has shrunk by over 40% from 151 to 90 gallons per day.
Bruce Flory, Principal Economist at Seattle Public Utilities
Ninety-eight percent of the Cedar River Watershed is covered in forest. These trees protect water quality by filtering run-off and preventing erosion. The 88,000 acres of forest span nearly 5,000 feet of elevation, from lowland forests to the mountain ridges of the upper watershed. These forests are dominated by evergreen conifers such as Douglas fir, western hemlock, Pacific silver fir, and mountain hemlock.