First Flush Diverter - What does it do?
The First Flush Diverter captures and diverts the first few litres of rainwater that wash off from your roof and gutters, preventing it from entering your water tank. Those first few litres of water are often contaminated, by dust (especially if you live in a windy area), airborne pollutants (if you live near an airport or factories), animal fecal matter (mostly from bird droppings) and leaf debris. Click here to see Recommended First Flush Diverters.
How does a First Flush Diverter work?
The water container of a First Flush Rainwater Diverter is a vertical PVC pipe with a 80mm or 110mm diameter. Inside this pipe is a ball system - a flotation ball that floats on top of the water. When the water level rises through the vertical pipe and reaches the top, the ball floats at the surface of the water and closes the pipe hermetically, directing the water overflow into your rainwater tank. At the bottom of the First Flush Diverter, the end cap is fitted with a ball valve (or similar) to empty the contaminated water after the rain.
What are the benefits of a First Flush Diverter?
By filling up your tank with cleaner water, the First Flush Diverter will help you:
- limit the growth of algae, bloodworms, harmful bacteria and protozoa
- limit the build-up of sludge, contaminants and sediments
- extend the life of the water pump and filter cartridges connected to your tank
Where do you install a First Flush Diverter?
A First Flush Diverter should be installed just before your rainwater tank, after a Leaf Catcher. The Leaf Catcher first diverts big debris and leaves, and the First Flush removes smaller debris, animal droppings, pollutants and dust, before they can enter the rainwater tank.
How big should a First Flush Diverter be?
The bigger the roof, the bigger the First Flush Diverter needs to be. To remove most dirt off a roof area of 50m², a First Flush Diverter should ideally be able to collect about 25 litres of water. This represents a length of 2.5m for a 110mm First Flush Diverter, or 5m for an 80mm First Flush Diverter.
Is a First Flush Diverter recommended when harvesting rainwater?
At EcoDepot we always recommend using a First Flush Diverter. It extends the life of your pump and filters, and limits the growth of unhealthy bacteria in your rainwater tank, such as E. coli and Giardia.
- Complete collection of rainwater harvesting solutions proposed by EcoDepot
- 110mm First Flush Diverter
- 80mm First Flush Diverter
- Watch: How to install a First Flush Diverter and a Leaf Catcher