Millions of Wisconsin residents rely on private wells as the only source of potable water in their homes. Unfortunately, most of these wells are rarely (if ever) tested for bacteria or other contaminants. Another major news story today demonstrates the downside to the lack of knowledge of the water quality in these wells. The article estimates that more than 20,000 homes could be drinking well water with high arsenic levels. Some of the tested homes had levels that are hundreds of times greater than the federal standard for this toxic substance. Interestingly, one of Microbe Detective’s partners, Dr. Andrew Jacque (ajacque@wqinvestigations.com) has found that bacterial biofilms likely play a role in the solubilization of metals (such as radium, arsenic and others) in groundwater wells. As a result, it may be possible to reduce levels of metals by controlling the bacteria in the well.