Actually, we were told about that...

Lake Erie, which is a source of drinking water for the Toledo water system may have been impacted by a harmful algal bloom (HAB). These organisms are capable of producing a number of toxins that may pose a risk to human and animal health. HABs occur when excess nitrogen and phosphorus are present in lakes and streams. Such nutrients can come from runoff of over-fertilized fields and lawns, from malfunctioning septic systems and from livestock pens.

http://www.toledonewsnow.com/story/26178506/breaking-urgent-notice