Wells

If you stand at practically any point on Earth, there is water moving through the ground beneath your feet. Groundwater provides about half of the world’s population with drinking water and nearly half of all water used to irrigate crops. It sustains rivers, lakes and wetlands during droughts. Groundwater is a renewable resource, but it can take decades or even centuries for some aquifers to recover after they are depleted. Current understanding of this challenge is based mainly on where and how frequently people record measurements of water levels in wells. In a newly published study, our team of data scientists, water specialists and policy experts compiled the first global-scale dataset of these levels. We analyzed millions of groundwater level measurements in 170,000 wells located in over 40 countries and mapped how groundwater levels have changed over time. Our study has two main findings. First, we show that rapid groundwater depletion is widespread around the worl...

About 23 million U.S. households depend on private wells as their primary drinking water source. These homeowners are entirely responsible for ensuring that the water from their wells is safe for human consumption. Multiple studies show that, at best, half of private well owners are testing with any frequency, and very few households test once or more yearly, as public health officials recommend. Even in Iowa, which has some of the strongest state-level policies for protecting private well users, state funds for free private water quality testing regularly go unspent. Is the water these households are drinking safe? There’s not much systematic evidence, but the risks may be large. The U.S. Environmental Protection Agency still relies on a 15-year-old study showing that among 2,000 households, 1 in 5 households’ well water contained at least one contaminant at levels above the thresholds that public water systems must meet. While other researchers have studied thi...