Instead, rainwater is collected from the roof and stored in underground tanks before being pumped for use around the property.
A small number of systems filter and treat the water to a high standard to make it suitable for drinking, most just use filtration and the water is not suitable for drinking, bathing or cooking purposes.
Rainwater from the roof will contain bird droppings plus other bacteria, yeasts and moulds from decaying leaves and vegetation.
People with low or suppressed immune systems are much more vulnerable to some of the pathogens often found in these water systems such as legionella and Pseudomonas aeruginosa.
A simple and inexpensive drinking water test includes a check for E.Coli which, if found, is often an indicator of other pathogens being present.