SAN FRANCISCO (KTVU) - In the last few days, many Bay Area storm sewers got their biggest flush out, spewing all kinds of nasty materials out into the Bay.Most Bay Area cities have two sewer systems, one for human waste, the other for storm runoff.
In runoff systems anything that goes into the sewer or is already in it ultimately goes into the Bay. Then huge storms come along, which can dislodge toxics, some of which are stuck in sewers for decades.