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First Flush Delta Commercial

First Flush Delta Diverters
The Delta Commercial is available to suit 150mm and 225mm downpipes. Allowing you to enjoy the easy install benefits of using 100mm pipes for the first flush chamber. For larger volumes, consider the Delta manifold installation options
Size 150mm WDCL15
Size 225mm WDCL22
  • 150mm
  • 225mm
First Flush Delta Extra Chamber

Delta High Volume Chamber

Easily divert large volumes of first flush with the Delta High Volume Chamber. Using multiple 100mm pipes to create the diversion chamber, the Delta’s revolutionary design makes installation simple. The Delta chamber is customizable up to 2 metres. Every 1m of Delta chamber = 73 litres of diversion.

For larger volumes, consider the Delta manifold installation configurations.

Delta Commercial 150mm Kit

Integrated ball and seat

This unique design ensure that the first flush ball remains close to the seat, even in high flow events, ensuring the diverter seals as soon as the chamber is full. No more lost balls when cleaning your outlet either!


Arv Web Kit

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


First Flush diverters help you plan for volume by allowing you to choose your catchment volume with custom catchment size and/ or an advanced release valve.

First Flush Diverters help divert the first flush, through their design. They are installed using a T junction or high flow inlet to which the diversion chamber is fitted. As the chamber fills with the initial dirty water from your roof, a ball rises until it seals the inlet, allowing the rest of your rainwater, which is much cleaner, to flow directly to your tank.

Learn more about the 4 pillars of designing a Rain Harvesting system. 

The Rain Harvesting steps addressed:

Limit sources of contamination     Plan for volume

Filter leaves and debris                    Divert the first flush

Secure the system                             Manage standing water

Consider a safety net                        Monitor and maintain

  • Delta Diversion Chamber Calculator

  • Maintenance

    It’s important to ensure that your first flush diverter outlet remains clear of any debris. If your outlet becomes blocked, the chamber will not empty and the first flush of water will not be diverted when it rains.

    To ensure the flow of water out through your Advanced Release Valve, periodically remove from the Transparent Rapid Release Exit Funnel to check for any build-up of matter. Remove primary filter plus ball, and clean if required.

    Periodically check that the Advanced Release Valve batteries have charge. This is indicated by the flashing light.

    To protect your Advanced Release Valve from freezing or “winterising”, remove the timer prior to the first frost or freeze and store it indoors until spring. Remember to remove the batteries from the battery compartment.

    For best results and minimal maintenance, rain heads with 0.955mm aperture mesh such as Leaf Eater Rain Heads
    must be installed upstream of the Delta First Flush to limit the entry of debris that can reach your diverter.

  • Photo Gallery

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90mm (with Easy-Clean)

Your selection

Add Rain Harvesting or Plumbing products to your list.

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