Requires the department to enhance the ambient groundwater monitoring and assessment program in order to accurately characterize long-term trends in the state's groundwater levels and water quality. The program may be improved in phases and must include: (1) Standardizing methods, quality assurance, and data management practices for measuring groundwater levels and quality; and

(2) Creating a central database and migrating existing department of ecology and water resource inventory areas data to the central database by June 2009.

Provides, by June 30, 2011, the department of ecology shall conduct two voluntary pilot groundwater assessments in water resource inventory areas experiencing serious or critical withdrawals. One pilot groundwater assessment must be initiated in western Washington and one pilot groundwater assessment in eastern Washington.

Provides, by June 30, 2009, the department of ecology shall prepare a data gap analysis that evaluates existing groundwater information on water levels and water quality within each water resource inventory area of the state.