Water in New Mexico isn’t universally poisonous, but specific areas and sources have known contamination issues, primarily Arsenic (naturally occurring, affecting smaller systems/wells) and PFAS (”forever chemicals” from military/industrial sites like near Holloman AFB), posing serious health risks, requiring residents to rely on tested community systems or bottled water in affected zones like Sunland Park or La Cieneguilla. The state health department monitors water quality, but some private wells and smaller systems struggle to meet standards for these contaminants.
There is a statewide program underway to treat brackish water for various uses such as agriculture. In general for alluvial aquifers water quality decreases with depth and treatment for various uses is required. In SE NM it naturally occurs in the Capitan confined aquifer with water quality decreasing to the southeast. The irony is that oilfield produced water is excluded from the program.