Central Marin Sanitation Agency

Child Splashing in rain

During wet weather, stormwater and groundwater inflow and infiltration into the sanitary sewer collection system causes high wastewater flows to the treatment plant.

During these conditions, CMSA blends chemically enhanced primary-treated effluent from the primary clarifiers with fully-treated effluent from the secondary clarifiers prior to chlorination, dechlorination, and discharge into the Central San Francisco Bay.

Below are the blend events for the current wet weather season. The Agency maintains records of blend events from prior wet weather seasons.


Blending Events

Start End Duration
(Million Gal.)