In the United States, a new public opinion poll from Gallup found that Americans continue to be concerned about the quality of their drinking water. Fifty-six percent of respondents expressed “a great deal” of worry about drinking water pollution. Drinking water pollution appears to be the top environmental concern for Americans, followed by pollution of rivers, lakes, and reservoirs.

In Louisiana, lawmakers are considering a grading system that would issue report cards on the condition of the state’s community water systems. The state Senate approved the measure last week by unanimous vote. It now moves to the House for consideration. The Associated Press reports that the grading system would evaluate water utilities based on benchmarks like history of federal and state water quality violations, financial sustainability, operations and performance, and customer satisfaction.

In California, a severe drought is rekindling fears that groundwater wells serving rural households will once again dry up en masse. Wesley Harmon is a well driller in the Central Valley town of Riverdale. “It’s going to be ugly,” Harmon told the Fresno Bee. “It’s going to be real bad.” Harmon is already seeing demand spike for new and deeper wells. Seven years ago, the last time the area was as dry as it is today, thousands of household wells failed in the Central Valley. Social justice advocates are worried that poor and Latino families in the agricultural valley will again bear the brunt of the crisis. Farmers tend to lean more heavily on groundwater in years like this one, when rivers and reservoirs are low. That causes the water table to drop below the level of many household wells.

The risks of dry wells are not only in the Central Valley. This week Circle of Blue reports on a study that examined the global risk of failing wells.

Wells serving many of the world’s rural households, farms, and factories are at risk of running dry if groundwater levels in their areas continue to decline.

According to a new analysis of 39 million wells, between 6 percent and 20 percent are no more than five meters below the top of the water table. The math in these scenarios is unforgiving.

“This implies that millions of wells are at risk of running dry if water tables decline just a few meters,” Scott Jasechko of the University of California, Santa Barbara, told Circle of Blue. Jasechko and co-author Debra Perrone, also of UCSB, published their peer-reviewed study online on Thursday in the journal Science.

Drilling a deeper well is often an inadequate solution, Perrone said. It might spur a race to the bottom and worsen local groundwater drawdowns. Because more electricity is needed for pumping, deeper wells increase operating costs. However, the analysis found that deeper wells are not being drilled in all areas. In some places, new wells are just as vulnerable to declining water tables.

Lifting water from greater depths also raises questions of equity, Perrone said. Not every household can afford to spend $10,000 or more on a new well. Tapping other water sources might not be feasible. When a family has no other option, they might sell the land or move.

Constructing a global groundwater well appraisal was no simple task. Jasechko and Perrone combed through 134 databases, often requiring multiple inquiries per country. Canada, for instance, keeps its groundwater records at the provincial and territorial level.

Forty countries representing half of global groundwater pumping are included in the data, which refers to well locations, depths, purposes, and dates of construction. Though the results describe global patterns, Jasechko said the analysis is supported by locally relevant details.

Jasechko and Perrone included as many countries as possible in the analysis, but they were constrained by the quality of the record keeping. India, Mexico, South Africa, Thailand, Brazil, most of Europe, and the United States were among the countries that made the cut.

All told, they spent six years on the project.

Perrone believes it was time well spent. Groundwater research that she began in the western United States extends globally. If wells are the hardware, Perrone is now assessing the software, meaning the legal and regulatory systems that match water supply and demand. She wants to see what solutions are working.

“We’re most interested in how to use this information to inform change,” Perrone said. “To elevate groundwater to the importance it should have.”