How can collected rainwater be used? Certainly for outdoor non-potable uses like irrigation and some municipalities allow rainwater to be used inside a home or building for toilet flushing.
Codes vary from state to state. For example, The City Of Atlanta allows a homeowner to collect rainwater, filter it to potable water standards and bring it into the home for complete home use ( drinking, dishwasher, shower, laundry).
Why should storm water be harvested? First of all, storm water is the # 1 pollutant in our lakes and rivers. These water sources are also our #1 drinking water resource. As development expands so does storm water run off and chemicals that are being washed into our drinking water resources. Water is much easier to keep clean than it is to clean once dirty.
Harvesting rain, the cleanest water on earth solves a multitude of problems. It has been proven that if you harvest rainwater and reduce storm water run off the river flow will actually increase along with subsurface water reserves. Pollution is reduced and drinking water source provide a cleaner water to be processed into drinking water.