FAQs

What causes a sanitary sewer overflow?: Causes of sanitary sewer overflows include grease blockages, root blockages, debris blockages, sewer line flood damage, manhole structure failures, vandalism, pump station mechanical failures, power outages, storm or groundwater inflow/infiltration, lack of capacity, and/or contractor caused blockages.

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Public Works - FOG Program

1. What is FOG?: FOG stands for Fats, Oils and Grease. These are by-products of food service establishments (FSEs), automobile repair facilities and car washes.

2. What does FOG do, why is it bad?: FOG coats the inside of the sanitary sewer mains and reduces the capacity of the mains. Eventually it will cause the flow of wastewater to back up and trigger an overflow.

3. What is a "sanitary sewer overflow? (SSO)?: A “sanitary sewer overflow” is defined as a discharge to ground or surface water from the sanitary sewer system at any point upstream of the treatment facility. Temporary storage and conveyance facilities (such as wet wells, regulated impoundments, tanks, high lines, etc.) may be part of a sanitary sewer system and discharges to these facilities are not considered sanitary sewer overflows, provided that the waste is fully contained within these temporary storage/conveyance facilities. Sanitary sewer overflow is also defined in State Water Resources Control Board (State Water Board) Order No. 2006-0003-DWQ,
Statewide General Waste Discharge Requirements for Sanitary Sewer Systems, found at
http://www.waterboards.ca.gov/resdec/wqorders/2006/wqo/wqo2006_0003.pdf.

4. What causes a sanitary sewer overflow?: Causes of sanitary sewer overflows include grease blockages, root blockages, debris blockages, sewer line flood damage, manhole structure failures, vandalism, pump station mechanical failures, power outages, storm or groundwater inflow/infiltration, lack of capacity, and/or contractor caused blockages.

5. What is the content on sanitary sewage?: Contain high levels of suspended solids, pathogenic organisms, toxic pollutants, nutrients, oxygen demanding organic compounds, oil and grease, and other pollutants.

6. What is the impact from a Sanitary Sewer Overflow?: Sanitary sewer overflows can cause temporary violation of applicable water quality objectives, pose a threat to public health, adversely affect aquatic life, and impair the public recreational use and aesthetic enjoyment of surface waters in the area.

7. What can residents and businesses do to reduce FOG and prevent sanitary sewer overflows (SSO)?: Residents and businesses have an important role in reducing FOG and helping prevent SSOs.