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4" Post/Wall-Mounted First Flush Water Diverter Kit

4" Post/Wall-Mounted First Flush Water Diverter Kit
Images may be inaccurate. See specs table below to ensure accuracy.
Low maintenance
No mechanical parts
Easy installation, just add 12" pipe length and glue
Improves water quality, protects pumps and internal appliances
Prevents sediment and debris from entering the rainwater tank/cistern



Rain Harvesting Post/Wall Water Diverter, part# WDPW99 is a versatile unit that can be mounted on a wall or post, 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 6 and 38 gallons.

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 12″ pipe. The kit includes a saddle and a galvanised steel wall-mounting bracket.

How much water to divert

It is important to prevent heavy sediments and other roof pollutants from entering the rainwater tank/cistern. The amount of water diverted should be a minimum of 12.5 gallons per 1000 square feet of roof area (or 0.0125 gallons per square foot). In calculating the amount of water to divert, consideration can be given to (1) the surface area of the roof, and (2) the amount 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.

First Flush Water Diverter Table

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

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/cistern.

Post/Wall Water Diverter Dual Pipes

Installation Instructions

Determine the length of pipe required using the table above.

Inlet End: The ball seat #6 is inserted into the top of the end cap as shown.

– For 3″ Schedule 40 PVC pipe infeed – insert the ball seat #6 and attach the infeed pipe hard down on top of ball seat #6.

– For 4″ Schedule 40 PVC pipe infeed – insert the ball seat #6 and glue the 3″ keeper ring (1.1″ long) hard down on top of the ball seat #6 to keep it firmly in place.

Outlet End: The outlet requires only 3″ 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.

Post/Wall Water Diverter Reference Chart

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Additional Information

Store ID X8349146
Manufacturer Info
Product Part # WDPW110
Former MPN's WDPW99
Manufacturer Rain Harvesting
Installation Instructions Rain Harvesting WDPW110 Installation Instructions
Physical Features
Weight (lbs) 4
Color Natural White
Product Type Rainwater Diverter
Shipping Info
Shipping Locations Georgia
Shipping Zip Codes 30309
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