Abstract: A batch water treatment system is provided in which ozone is the reactive agent. The system includes a holding tank containing untreated water in communication with a reaction tank in which ozone is dispersed under pressure through a plurality of foraminous diffusers which are connected to a modular ozone generator. Impurities contained in the water are oxidized or broken down by the ozone into forms capable of filtration, and as this treatment process progresses the water is circulated through a conduit to a monitor which measures the level of impurities in the water. Once a predetermined proportion of impurities are broken down and filtered from the system, the monitor automatically activates a drain line to evacuate the reaction tank of the treated water and then refills it with more untreated water from the holding tank to repeat the process.