Rain Harvesting First Flush Diverter | Wall/Post Mount | 3"-4" Filter
Rain Harvesting WDPW110 First Flush Diverter Kit – Post/Wall Mount
Targeted First Flush Protection for Compact Rainwater Systems
The Rain Harvesting WDPW110 First Flush Diverter Kit is purpose-built for wall or post-mounted installations, making it ideal for small residential systems, sheds, or outbuildings. This compact yet effective diverter removes the initial dirty runoff from your roof before it enters your tank, significantly improving water quality with a sleek, space-saving design.
A high volume first flush diverter, designed specifically for mounting on a wall or any vertical structure. The unique manifold design uses standard 100mm or 4 in. pipe to create a high capacity storage and diversion chamber for your first flush. Using these smaller pipe sizes makes it easier to source pipe and assemble the system, when compared to using large diameter pipe on traditional high volume diverters.
Highlights
The Rain Harvesting WDPW110 First Flush Diverter Kit is purpose-built for wall or post-mounted installations, making it ideal for small residential systems, sheds, or outbuildings. This compact yet effective diverter removes the initial dirty runoff from your roof before it enters your tank, significantly improving water quality with a sleek, space-saving design.
- Divert large volumes of water, easily - easily divert large volumes of water with delta's unique manifold design which only requires you to use smaller diameter pipe
- Ultimate first flush control - by setting the regularity of your first flush diversion, you can optimize how often your first flush diverter drains
- Catch-all tee improves clean water yield
- Easy maintenance - the catch-all tee ensures no water skips across the tee until the first flush of water is complete - which means you only capture the best quality water
- Just add pipe - the first flush delta in-ground comes with all fittings you need to set the system up just add the pipe to create the storage chamber
- Divert large volumes of water, easily - easily divert large volumes of water with delta's unique manifold design which only requires you to use smaller diameter pipe
- Ultimate first flush control - by setting the regularity of your first flush diversion, you can optimize how often your first flush diverter drains
- Catch-all tee improves clean water yield
- Easy maintenance - the catch-all tee ensures no water skips across the tee until the first flush of water is complete - which means you only capture the best quality water
- Just add pipe - the first flush delta in-ground comes with all fittings you need to set the system up just add the pipe to create the storage chamber
Product Details
Key Features
Model: WDPW110
Application: Suits 3" (90mm) and 4" (100mm) round downpipes
Mounting Style: Wall or post-mounted
Material: UV-stabilized PVC construction
Capacity: Adjustable via diverter pipe length
Included Components:
Diverter T-junction
Ball and seat mechanism
Mounting brackets
End cap and slow-release drain valve
✅ Benefits
Space-Saving Design – Mounts cleanly to walls or posts when vertical downpipe space is limited
Improves Water Quality – Removes the most polluted water from each rain event before it enters your tank
Adjustable Volume – Customize the diverter pipe length to suit your roof size and local rainfall
Durable Build – UV-resistant materials ensure reliable performance in outdoor conditions
Easy Maintenance – Accessible components allow for quick inspection and cleaning
Installation Overview
Choose a wall or post location near your downpipe
Connect the diverter kit inline with a 3" or 4" downpipe
Adjust the diverter pipe length to match the desired first flush volume
Secure with included brackets and test slow-release valve functionality
Shipping & Handling
Package Dimensions: 24" L × 10" W × 8" H
Shipping Weight: Approximately 5 lbs
Packaging: Individually boxed with mounting hardware and instructions
Delivery Method: Ships via standard ground service
The benefit of one larger unit is that it can be easier to maintain than a series of smaller diverters installed at each downpipe.
The first flush of water from the roof can contain amounts of bacteria from decomposed insects, bird and animal droppings and concentrated tannic acid. It may also contain pollen, water borne heavy metals and chemical residues, all of which are undesirable elements to have in a water storage system. Rain Harvesting's range of First Flush Water Diverters (or Roof Washers) capture the first most contaminated rainwater from the roof and gutters, automatically diverting the subsequent cleaner rainwater to the storage tank.
Diverter end caps contain 6.52 gallons.
Requires six sections of 4" PVC pipe which can be purchased online or at a local plumbing supply.
Product Improvements from Previous Design:
- No More Bulky 12" Pipe
- Integrated Ball and Seat
- Divert Larger Volumes
By allowing you to determine the frequency of first flush, the Advanced Release Valve ensures that the Delta’s first flush diversion is optimized. The transparent, rapid release exit funnel reduces build up and blockages while allowing for easy visual inspection.
Diversion Recommendations for the Roof |
Minimal Pollution: divert 0.0125 gallons per square foot of roof area Substantial Pollution: divert 0.05 gallons per square foot of roof area Example for a minimal polluted roof of 1,000 square feet: Example for a heavily polluted roof of 1000 square feet: |
PVC Pipe Specifications |
3" Downspout diverters: Use 3" Schedule 40 PVC 4" Downspout diverters: Use 4" Schedule 40 PVC Post/Wall and In-ground First flush diverters: Use 4" Schedule 40 PVC |