Erosion chlorinators were evaluated to determine their reliability in delivering a constant chlorine dose for disinfecting potable water sources. Several erosion chlorinators are on the market, but only one has been approved for use with potable water systems in the United States. The erosion chlorinator was shown to provide unstable dose rates when operated in a continuous-flow mode. Intermittent flow operation provided a more stable dose rate, but the greatest degree of dose stability resulted from a flow rate of 40 gpm, with operating periods of 10 minutes on and 10 minutes off. The use of erosion chlorinators should therefore be limited to intermittent operation.