It is illegal to collect rainwater in a few states so check your state laws first. You could use rainwater to help you save money on your water bill. You can use rainwater to water plants or gardens, and some people use it to flush their toilets.
You can catch rainwater and use it. Many people collect rainwater in barrels and use it when it is not raining to water their lawns. The barrels are placed under downspouts to collect the water drainging from the gutters. This helps them save money on their water bills and helps conserve water.
Yes you can use rain water caught and stored in a cistern, it can used for various purposes like cleaning vessels, watering plants, bathing, washing clothes, water used for toliet purposes, or for any other purspose. It should'nt be used for drinking purposes, if you are too particular then you should boil, filter and then use it for drinking.
Yes, you can catch rainwater and use it to water your plants, flush your toilet, clean your house, wash your dishes, wash your pets, wash your clothes, and even drink it if you don't live too close to a pollution source like a factory.