Provided that you live in an area without high levels of air pollution, the rainwater that falls on your property will typically be safe as potable water. If you want to make extra sure, you can filter or boil the water first – or both! However, ensuring the cleanliness of your harvesting system is important.
The first step is to make sure your tank is made from food-grade materials, either fitting it with a food-safe tank liner or a UV stabilized polyurethane water tank. Ensure that the roof being used for rainwater harvesting isn’t made from treated wood or bituminous products, and hasn’t come into contact with lead paint or a chimney from a wood burner. Read the full guide for more info on harvested rainwater.