The length of time rainwater can be stored before it starts to develop a foul odor or is no longer considered “fresh” depends on the water quality of the stored water and the characteristics of your individual system. In a system that has been properly designed, installed, and maintained, rainwater should remain fresh and usable for up to 1 month. Certain site conditions and installation details of a system may lengthen or shorten the duration the water will remain fresh and usable. Adding an Ozone injection and/or recirculation system to your rainwater harvesting system can drastically improve the quality of your stored water and extend the amount of time rainwater can be stored.