Swimming bans at beaches are temporary 1-3 day events that happen at only a few beaches a few times a year. They are triggered by a specific event: heavy rain.
Normally the sewer system is self-contained, but during heavy rains the storm sewer system overflows into the lake, causing a temporary rise in bacteria in some places. It goes away after a few days.
Municipal tap water is treated with anti-bacterial agents, so bacteria has no effect on the water supply.
Last edited by UpstaterInBklyn; 05-02-2008 at 07:19 PM..