Code of Federal Regulations: Title 40 – Protection of Environment
Hypochlorous Acid may be applied to food-contact surfaces in public eating places, dairy-processing equipment, and food-processing equipment and utensils. When ready for use, the end-use concentration of all hypochlorous acid chemicals in the solution is not to exceed 200 ppm determined as total available chlorine.
In drinking water, hypochlorous acid should not exceed 4 mg/L (4 ppm). See the EPA National Primary Drinking Water Regulations: Click Here