However, when rainwater falls from the sky, substances in the air and the earth melt into the rainwater. Fortunately, when rainwater penetrates the ground, it turns into mineral water. While useful for many things, rainwater isn't as pure as you might think, so you can't assume it's safe to drink. Rain can carry different types of pollutants into the water you collect (for example, bird droppings on the roof could end up in the barrel or water tank).
Rainwater can carry bacteria, parasites, viruses and chemicals that could make you sick, and it has been linked to disease outbreaks. Freshwater is defined to have a salt concentration of less than 0.05%, while salt water (such as the ocean) has a salt concentration between %3-5.Yes, water molecules need a nucleation point to condense into a drop of water (it's something I remember from an episode of Bill Nye when I was younger). If you collect and store rainwater for drinking, you have an individual water system and are responsible for ensuring that the water is safe. The best and safest way to collect rainwater is through the use of storage containers specifically manufactured by a reputable company that produces steel rainwater tanks for the purpose of directly collecting rain.
When rainwater is used as a source of supplemental water, homeowners should ensure that rainwater cannot enter pipes that contain drinking water. When water vapor returns as rain, it has picked up impurities from the air it moved through. Consider adding a grate to the water inlet or emptying the rain barrel at least every 10 days to prevent mosquitoes from using the rain barrel as a breeding ground.