What is a First-Flush Diverter?

This post is part of the series How to Build a Simple Rainwater Collection System.

What is a First-Flush Diverter?A first-flush diverter helps keep your rainwater harvesting system clean by enabling the removal of dust, other debris, and any fecal matter that collects on your roof and in your gutters between rainfalls, so it is flushed out at the very beginning of the water collection process.

What is a First-Flush Diverter?
Click to view larger version of First Flush Diverter Diagram

The cleaner your water is as it goes into your system, the cleaner your water will be when you use it. Studies have shown a tremendous drop in fecal bacteria levels when the roof is flushed before water enters the tank. Bacteria also like to live in decaying leaves and other organic matter that collects at the bottom of the tank. A first-flush diverter “washes” the roof, so there is less rubbish on the tank’s bottom.

Do you want to see more articles about how to build a simple rainwater harvesting system? Check the “Notify me of new posts by email” button below.

Ken Blair
A rainwater collection systems designer and consultant, Ken has designed and installed residential and commercial systems, primarily in the northwest United States for more than 10 years and, in 2014, began consulting and managing builds in other states. Ken is an accredited ARCSA Professional Designer / Installer and Life Member, the Northwest Regional ARCSA representative and advisor to its education committee and is available to speak about Rainwater Collection Systems design and builds.

Ken is a United States Navy veteran, having served on active duty during the Vietnam War era. He attained the rate of E-4 Machinist Mate.

A career entrepreneur, Ken created a new business focus with a commercial dive company in Hawaii in the mid 1980′s to respond to and clean up oil spills, oil spill equipment training, service and maintenance for the oil co-op service industry. Ken is passionate about having a positive impact on the environment and is also a founding director of BANK-ON-RAIN (2011-2014), whose mission is to create grassroots solutions for rainwater collection for consumption and agriculture in developing areas of the planet.