Marine water quality in Oakland Bay is checked monthly. The Washington Department of Health samples 19 marine stations throughout Oakland Bay as part of the Shellfish Program and reviews the data annually. Squaxin Island Tribe concurrently samples the nine largest streams flowing into Oakland Bay and monitors the marine waters and sediments at the north end of the bay as well.

The Mason County Public Health Water Quality Program is concerned with both ground and surface waters in order to protect public health, environmental health and water as a resource. It is the responsibility of the Water Quality Program to prevent pollutants from entering ground or surface waters, to monitor for evidence that suggests pollution sources and to correct sources of pollution. They test shoreline stream, culverts and seeps and follow up with sanitary surveys and septic system testing in areas of poor water quality. The county also maintains a septic system operation and maintenance database and sends out regular reminders to assist citizens in getting routine septic system maintenance done.

The Squaxin Island Tribe has an additional ongoing investigation of bacteria survival and reproduction on intertidal sediment. It is part of an effort to identity when and why bacteria spike during the summers in upper Oakland Bay.

Mason County Public Works is experimenting with a new method of treating stormwater. A mycelial mat grown along the sides of stormwater ditches may provide a natural way to reduce the level of fecal coliform bacteria, hydrocarbons and metals that are conveyed by stormwater drainages to the bay. Initial test results are promising. See below for more information and results.