Review of Guidelines for Shock Chlorination in Private Wells

Microbial contamination of groundwater from private wells can pose a significant health risk to rural Canadians. To mitigate risk, Health Canada currently recommends shock chlorination along with microbial well testing, voluntary measures most often performed by the homeowner. However, infrequent testing and paucity of research assessing the effectiveness of shock chlorination guidance as practiced by homeowners, may leave private well users vulnerable to persistent or periodic groundwater contamination. Although shock chlorination is important for both health protection and well maintenance, it is not sufficient on its own to guarantee safe drinking water. Rather, shock chlorination should be integrated into a well stewardship approach consisting of adequate well protection and maintenance, a water-monitoring program, and responsible decommissioning of abandoned wells.