Post/Wall Stand Water Diverters

First Flush Water Diverters


Description Code
Post/Wall/Stand Mounted First Flush Water Diverter
300mm Post/Wall Mounted(Inlet fits 90mm pipe or 100mm female fitting) WDPW01
300mm  Galvanised Steel Stand# WDAC01
300mm PVC Pipe WDAC09
#Order In-Ground Kit (WDIG01) if stand is required
to Divert
Pipe Diverter
Litres Length
Total Height
20 225 590
30 365 730
40 500 865
50 630 995
60 780 1145
70 905 1270
80 1050 1415
90 1180 1545
100 1310 1675
120 1610 1975
130 1735 2100
150 2005 2370

Compliance: Australian
Standard AS/NZS 4020:2005
(Testing of products for use in
contact with drinking water)

The First Flush Post/Wall Stand Water Diverter is a versatile unit that can be mounted on a wall, post or stand, to hold larger volumes of water. It can be adapted to suit a wide range of applications and will manage single or multiple pipes coming from the roof to divert between 20 and 150L.

The kit is easy to freight, and the diverter volume can be made on site to match exact requirements – just add the appropriate length of 300mm pipe. The kit includes a saddle and a galvanised steel wall-mounting bracket. A galvanised steel stand is an optional alternative to post or wall mounting.

Features and Benefits

  • Prevents sediment, bird droppings, spiders, insects, mosquito eggs and debris from entering the rainwater tank.
  • Improves water quality, protects pumps and internal appliances.
  • Ideal to use in conjunction with a rain head.
  • Easy installation, just add 300mm pipe length and glue.
  • 300mm pipe can be purchased from Rain Harvesting.
  • No mechanical parts.
  • Inlet fits 90mm pipe or 100mm female fitting.


How much water to divert

It is important to prevent heavy sediments and other roof pollutants from entering the rainwater tank. The amount of water diverted should be a minimum of 20 litres per 100 square metres of roof area (or 0.2L per m2). In calculating the amount of water to divert, consideration can be given to (1) the surface area of the roof, and (2) theamount of pollutants on the roof and gutters.

The following factors can be used as a guide in determining the volume of water to be diverted.


As a rule of thumb, the more water that is diverted the better the quality of water in the tank.

Multi pipe feed systems

These water diverters can handle more than one pipe

Single or multiple pipes coming from the roof can be connected into a “T” and coupled together so that the first flush from the roof enters the diverter chamber. The pipes are connected from the “T” into the tank.


Installation Instructions

Determine the length of pipe required using the table opposite.
Inlet End: The ball seat #6 is inserted into the top of the end cap as shown.
– For 90mm infeed – insert the ball seat #6 and attach the infeed pipe
hard down on top of ball seat #6.
– For 100mm infeed – insert the ball seat #6 and glue the 90mm keeper
ring (28mm long) hard down on top of the ball seat #6 to keep it firmly
in place.
Outlet End: The outlet requires only 90mm pipe. Assemble as shown making sure to insert ball #7 before attaching cap #12. Select one of the four control valves #13 and fit into hose connector #14. Save the remaining valves for possible later use.

Stands: It is important to line up the center of the chamber outlet with the weld on the stand. Make sure that the stand is bolted down securely and that the pipe work connected to the top of the diverter chamber is appropriately secured so that the diverter is stable and the unit is not stressed by bad alignment.