According to the Associated Press, the richest farm region in the world, California's San Joaquin Valley, is contaminated with unsafe amounts of toxic uranium in their tap water. 

"Government authorities say long-term exposure to uranium can damage kidneys and raise cancer risks..." (The Associated Press, Dec. 8, 2015).

Since 2010, $16.7 million has been spent on improving the state's public water system to handle toxic uranium levels. This does not include private wells owned by homeowners who have to treat and test their own water. Depending on the size, installation of uranium-removal facilities can range from $65,000 to millions of dollars.

Click here for the complete article from the Associated Press.

Associated Press 
US News