In Puget Sound, fecal pollution comes from both point-source origins such as combined sewer overflows and direct marine effluent discharge as well as non point-source origins such as surface water runoff, both of which increase with rainfall and river and stream discharge. In addition to serving as an indicator of pathogens, fecal bacterial pollution can also be an indicator of nutrient loading because sewage often contains high levels of nitrogen and phosphorous. Both point source (failing septic systems) and non-point sources (landscape features) contribute to fecal bacterial levels in Puget Sound.
Source: Puget Sound Science Review
Overview
Fecal bacteria are found in the feces of humans and other homeothermic animals. They are monitored in recreational waters because they are good indicators of harmful pathogens that are more difficult to measure.
