Hi Nicolas, At times I collect rain water direct to the tank and it is drinkable as it arrives. The water for my land based living for the past 22 years has all been rainwater collected from the roof of my house and we use it as is, no treatment, no filtration, no issues. We do live in a small coastal village of around 2000 so air pollution is not an issue. No doubt at times a few bird droppings must be on the roof but still no issues.