The study has shown that water from a roof can contain about 60 cfu 100ml of coliform bacteria relatively harmless to 50 000 cfu 100ml very likely to contain harmful pathogens and not safe to use and that a slow sand filter will vary somewhat in its ability to remove pathogens.
Is it safe to collect rain water on a roof.
Drinkable rainwater can be collected from most roof types including undamaged asbestos colorbond zincalume and galvanized steel.
This is called the first wash and will be discussed in detail in the first filtering chapter.
Unless the zinc content is particularly high it is safe to use on lawns and ornamental gardens.
And also that a first flush diverter will remove a considerable number of the pathogens but not enough to be safe.
Yes rain water is perfectly safe for drinking purpose and qualifies all who tests till the time it hits your rooftop where it interacts with the dirt stored there.
Germs and other contaminants while useful for many things rainwater is not as pure as you might think so you can t assume it s safe to drink.
However still this water can be used if the first flush of water is diverted from the roof tops.
The quality of water coming off of a roof during a rain tends to improve as the rain continues.
Most studies agree that it is a good practice to eliminate the first few gallons of rainfall that is collected from the roof.
It is important to find out if the material or the paint used on your roof or in your gutters could contaminate your rainwater.
Use it to wash cars and outdoor equipment and to rinse patios.
Safe roofing materials for rainwater harvesting.