The water supply of more than 2 million Californians has been exposed to harmful levels of nitrates over the past 15 years, a period marked by lax regulatory efforts to contain the colorless and odorless contaminant, a California Watch investigation has found.


Nitrates are the most common groundwater contaminant in California and across the nation. A byproduct of nitrogen-based farm fertilizer, animal manure, wastewater treatment plants and leaky septic tanks, nitrates seep into the ground and can be expensive to extract.


To read more, visit the San Franicisco Chronicle or the San Jose Mercury News.