For many Kenyans, borehole water has become the go-to solution as piped water grows scarce in cities like Nairobi and rural households alike. But experts warn that untreated borehole water can carry serious health risks that often go unnoticed until it is too late. Here are some of the reasons you need to consider before getting too comfortable with the consumption of borehole water. The geology of a location also determines whether borehole water contains dangerous trace metals such as lead and arsenic. The problem is worsened by the fact that most Kenyans do not test their borehole water regularly.