Environmental Assessment > Groundwater

Groundwater

Groundwater can be defined as water in the subsurface that saturates the rocks and sediment in which it occurs; the upper surface of groundwater saturation is commonly termed the water table.

Groundwater is one of Washington's most vital natural resources. In addition to being the primary drinking water source for the majority of Washington's 6 million residents, groundwater also supplies over 25 percent of the annual water needs of Washington's industrial, agricultural, and business interests.

During the summer months groundwater also cools and sustains the flows in most of Washington's lowland salmon-bearing streams. Groundwater systems are dynamic and continually adjust to short- or longer-term changes in land use, groundwater use, and climate.

The Environmental Assessment program conducts both focused and broader scale monitoring studies to help support the sustainable management of Washington's groundwater resources.

Groundwater Assessment in Washington State