Domestic-well failure mitigation and costs in groundwater management planning: observations from recent groundwater sustainability plans in California, USA

Domestic supply wells meet much of the world’s potable water demand. These wells tend to fail as regional groundwater levels decline from intensive agricultural groundwater use, especially during drought when additional pumping occurs. This work examines approaches for addressing impacts on domestic wells in much of the San Joaquin Valley in California, USA, where groundwater management is now required. Mitigation actions and their costs are considered to allow continued well operations as groundwater levels decline to target levels specified in groundwater management plans. The estimated total mitigation cost for groundwater-level declines to the planned management targets ranges from $42 to $96 million depending upon well retirement age. If groundwater levels decline further to defined limits below the management targets allowed during drought, costs increase by $78 to $153 million. There will likely be competition for specialized labor to implement the mitigation actions since agricultural wells will also be affected. Unless current groundwater management plans become more stringent and specify shallower groundwater depth targets, proactive mitigation should be considered for the most vulnerable areas to prevent impacts from growing beyond the capacity for timely mitigation and to avoid widespread failure of rural domestic water supplies. The cost of mitigation for impacted wells is estimated to be less than 2% of the benefit to agriculture from being allowed to pump groundwater in excess of management targets during a multiyear drought.