Systems and methods for producing ozonated water on demand. In particular, these systems comprise a water source, an ozone source, and a nozzle that mixes ozone and water to form a highly concentrated, ozonated water solution. Instead of requiring the ozonated water to be re-circulated to achieve a desired ozone concentration, the nozzle is configured to form the ozonated water solution in a single pass through the nozzle. Additionally, instead of requiring the ozonated water to be discharged into a pressurized tank to increase ozone absorption, the nozzle allows the ozonated water to be openly discharged. In some cases, the nozzle comprises a venturi with multiple ozone inlets to increase mixing. Additionally, in some cases the nozzle comprises a single pass mixing mechanism that mixes the water and ozone to form the high concentrate, ozonated water solution in a single pass through the nozzle.