The CampWater system uses ozonation followed by cartride filtration to remove arsenic via coprecipitation. The system utilizes ozione to oxidize iron and arsenic(III) to arseni(V). The arsenic bound to the iron precipitates is then removed by cartridge filtration. No additional floculatiopn, solids separation or clarification is required. The CampWater system was tested on a ground water source with 27 µg/L arsenic and 0.62 mg/L iron. Operating the system at 550 mV oxidation-reduction potential (ORP) and the natural water pH of 7.9 reduced the arsenic by 33%. Subsequent tests at 550 mv ORP showed that decreasing the pH to 7.5 improved arsenic removal.