"The water supply of more than two million Californians has been exposed to harmful levels of nitrates over the past 15 years," according to a report by California Watch. Nitrates are the most common groundwater contaminant, and are a problem in both rural and city water systems. In 1980, nine wells in California exceeded accepted limit for nitrates. By 2007, that number was 648 and scientists anticipate that number to continue to increase if steps aren't made to curb nitrate contamination.
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