Abstract: A water separator adapted for use in a gas monitor includes a gas inlet port, a gas outlet port, a two-stage gas/water separator section, and a fluid reservoir. The two-stage gas/water separator section includes a first portion defining a first chamber which communicates with the gas inlet and gas outlet ports via a connecting conduit, a second portion defining a second chamber which communicates with the first chamber and the fluid reservoir, and an intermediate portion interposed between the first and second portions and defining a constricted passage between the first and second chambers. The second chamber has a frusto-conical shape in longitudinal cross section.