The first water from a rainfall event washes the roof and can contain poor quality water which you do not want in your tank. The First Flush Diverter prevents dirty water from contaminating your water supply. A First Flush Diverter is sized according to the size of the roof, and can flush between 0.25 mm and 2 mm of rainfall, depending on how contaminated your roof is.
See our range of first flush diverters here.