Is Rainwater Safe?

"Not so surprisingly there is a huge difference in hardness, calcium, and alkalinity between the well water and the rainwater. Well water typically drains from underground water tables and is normally stored in natural underground tanks; so it will slowly leach minerals and metals from the surrounding ground. Consequently, well water will generally have higher mineral and metal content depending on local soil conditions. In comparison, rain water will not have these issues, but may be adversely affected by local air pollution and debris in the rainwater catchment and conveyance areas (i.e. roof, gutters, downspouts, and pipes)."

Acid Rain
"Dry deposition refers to acidic gases and particles. About half of the acidity in the atmosphere falls back to earth through dry deposition. The wind blows these acidic particles and gases onto buildings, cars, homes, and trees. Dry deposited gases and particles can also be washed from trees and other surfaces by rainstorms. When that happens, the runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone."