Sewer Overflow Advisories

A combined sewer overflow (CSO) occurs when storm water and sewage, carried in a single pipe, overload the sewer system and flow untreated into rivers and streams. CSO’s usually carry a variety of pollutants, including debris, chemicals, bacteria, and animal waste.

The Allegheny County Health Department's CSO Alert Program and ALCOSAN's Sewer Overflow Advisory Key (SOAK) are complimentary advisory programs to warn the general public of possible river contamination from CSOs.  While these programs do not prohibit or discourage river recreational activities, they do caution recreational users to limit contact with river water when boating, fishing, water skiing or engaging in other river recreational activities.

For current status and additional information regarding Sewer Overflow Advisories, please click on any one of the following links:

Sewer Overflow Advisory Key (SOAK)

Current Season SOAK Status History

ACHD CSO Flag Alerts

ACHD CSO Alerts - FAQs

CSO Flag Locations

CSO Alert Data 2012

CSO Alert Data 1995-2012

CSO / SSO Outfall Signage

CSO/SSO Outfall Signage Locations (Updated 4/1/13)

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