Nov. 14 on The Story: For decades, thousands of eastern Oregon residents have relied on private wells to supply them with drinking water — but now a crisis is unfolding, with a growing number of homeowners discovering that their well water has begun to carry dangerous levels of nitrates, which may cause miscarriages, birth defects and cancer. The explanation is straightforward up to a point: the wells all tap into a massive aquifer beneath the Lower Umatilla Basin, a regional hub of commercial farming and food production. Fertilizer and animal waste are big sources of nitrates, which can seep into the groundwater. But tracking the nitrates back to their sources — and stopping them — is more complicated. Watch more The Story videos: http://bit.ly/watchTheStory Follow The Story on Twitter: https://twitter.com/TheStoryKGW Follow The Story on Instagram: https://instagram.com/thestorykgw