Groundwater and surface water sampling is often done under the auspices of the Aquifer Mapping Program and other related hydrogeologic studies at the New Mexico Bureau of Geology and Mineral Resources. We use the water samples from wells, springs, and surface water bodies to help interpret the flow path of groundwater, identify the recharge areas, and evaluate groundwater residence time. Since our hydrogeologic studies officially began in 2007, we have developed and implemented our procedures for water sample collection. Water may be sampled for a number of analyses including major ion chemistry, trace metal chemistry, stable isotopes of oxygen and hydrogen, and several naturally occurring environmental tracers, which provide estimates of groundwater age. This document serves as a reference to describe the procedures we use for water sample collection and for sample analyses. We try to adhere to these procedures to the extent that it is possible.