RainHarvesting (WDDP111) 4" First Flush Diverter Valve
The 4" First Flush Diverter Valve (WDDP111) is an essential pre-filtration device for rainwater harvesting systems, designed to divert the first flush of roof runoff—which typically contains dirt, debris, and contaminants—away from your storage tank.
This unit installs easily at the base of a 4" vertical downpipe (pipe supplied by others). As rain begins, the first portion of water fills the diverter chamber, trapping pollutants. Once the chamber fills, cleaner water continues to the tank. The diverter is equipped with a manual flush valve for easy maintenance between rain events.
Product Details
Key Features
Diverts First Flush (Dirty Roof Runoff) Before Reaching the Tank
Mounts to Base of Standard 4" Downpipe (pipe by others)
Manual Drain Valve for Quick Cleaning and Reset
Enhances Water Quality and Protects Downstream Filters & Pumps
Rugged, UV-Stabilized Construction for Outdoor Use
Suitable for Residential, Commercial, and Agricultural Systems
Specifications
Part Number: WDDP111
Pipe Size Compatibility: 4” Schedule 40 or DWV (pipe not included)
Material: UV-Stabilized PVC or HDPE
Installation Orientation: Vertical, inline with downpipe
Drain Type: Manual flush valve at bottom
Typical First Flush Volume: Customizable by pipe length (usually 1.5–4 gallons)
Application: Rainwater harvesting, stormwater runoff management
Dimensions
Height: ~20–24 inches (depends on pipe length used)
Diameter: 4 inches (pipe-fit)
Weight: Approx. 2.0 lbs (without pipe)