The evidence keeps mounting that people living in impoverished, Latino towns around the San Joaquin Valley are in danger if they drink water out of their taps. Researchers this year linked dirty drinking water with many towns, such as Seville, Orosi and Tooleville in Tulare County. The culprit is widespread nitrates, which come from fertilizers, septic systems, animal waste and rotting vegetation. This month, a new study reveals people living in similar communities also are at a high risk of drinking arsenic in their water.