Southwestern Pennsylvania has an abundance of streams and rivers. However, effective stewardship of the quality of its waterways has long been a challenge. In heavily populated Allegheny County, even a modest rain causes sewage to be discharged into rivers and streams from inadequate municipal storm water and sewage systems. That raises bacteria to unhealthy levels, and boaters and other recreational users are warned to avoid the water. This indicator tracks the percentage of the recreation season that is lost each year to such contamination.