First Flush Water Diverter

First Flush Water Diverters - 90mm

How do they work?

Fitting an appropriately sized First Flush Water Diverter is critical to achieve good quality water. Water Diverters improve water quality, reduce tank maintenance and protect pumps by preventing the first flush of water, which may contain contaminants from the roof, from entering the tank.

When it rains, water slowly builds up in the roof guttering system before it exits through the downpipe. The first flush of water from the roofcan contain amounts of bacteria from decomposed insects, skinks, bird and animal droppings and concentrated tannic acid. It may also contain sediments, water borne heavy metals and chemical residues, all of which are undesirable elements to have in a water storage system.

Instead of flowing to the water tank, these pollutants are diverted with the initial flow of water into the chamber of the water diverter. The water diverters from Rain Harvesting utilise a dependable ball and seat system - a simple automatic system that does not rely on mechanical parts or manual intervention.

As the water level rises in the diverter chamber the ball floats, and once the chamber is full, the ball rests on a seat inside the diverter chamber preventing any further water entering the diverter. The subsequent flow of water is then automatically directed along the pipe system to the tank.

For a water diverter to work effectively, the contaminated water in the chamber must be sealed off. This prevents the water passing to the storage tank and ensure the water does not "syphon" off the contaminated water in the chamber. The simplest and surest way to do this is with a floating ball and seat.

A slow release valve ensures the chamber empties itself after rain and resets automatically. The diverted water need not be wasted water because the drain pipe from the diverter chamber can be fitted to a standard drip irrigation system.

Click Here to view animation of how a First Flush Diverter works.