The purpose of the Water Quality Program is to protect public health by preventing pollutants from entering both ground water surface waters, monitoring for evidence of pollution, and correcting sources of pollution. A successful water quality program will ensure that the long term quality of waters in Mason County are maintained so that the public is protected from waterborne illnesses, environmental degradation is minimized or avoided, and economic well-being is preserved (including recreation and shellfishing). overlooking water at mountains

Criteria set by the Washington State Departments of Ecology and Health for water quality parameters provide standards that all ground and surface waters must meet in Washington State.

The Mason County Water Quality Program conducts monitoring, lab analysis, long-term trend analysis, investigations, and emergency/complaint response in order to ensure that waters of Mason County meet the criteria. Additionally, the Water Quality Program seeks out and receives grants for projects intended to prevent waters from failing or restore waters to those standards. Criteria are set for biological, chemical and physical parameters. Although other measurements are routinely collected, the Water Quality Program is primarily concerned with biological contaminants due to the correlation with human illnesses.