Farmington and Espanola were the only two tanks on the narrow gauge system that was in the "V.B.W." category on system maps (very bad water). I think the only other location was somewhere in Utah . Monero tank had bad water and crews also avoided taking water there . For the uninformed .Bad water contains certtain solids that cause foaming in the boiler . For the uninformed , foaming is an extremely dangerous situation where an engine could be working water in the cylinders and scorching the crown sheet at the same time ! Usually foaming can be remedied by blowing out water ,but bad water can make the problem persist .