How can a roof help with water efficiency? Well once we’ve established rain collection tanks, we have to think about all the water absorbed by the roof that won’t be running into the gutters. By using an all metal roof, we can increase our water collection by 20%. In addition, metal roofs have no petrochemicals like composite roofs, so we don’t have to worry about such materials in our collected rainwater. Finally, all metal roofs are water proof, fire proof, and have a life of around 75 yrs. This means they don’t need to be replaced like regular roofs, and lower waste in our landfills.