It's not that dirty, but you do have to design for those concerns. Acid rain can be buffered by adding seashells (lime) in the tank. You can easily tip off th

It's not that dirty, but you do have to design for those concerns. Acid rain can be buffered by adding seashells (lime) in the tank. You can easily tip off the first N gallons of dirty rain (pollution, roof washing, etc) with a dead-end pipe with a dribble tube.