Does A First Flush Diverter Increase Rainwater Harvesting Efficiency?

What is a First Flush Diverter?

A First Flush Diverter is a simple, yet effective device that captures the first flow of water from the roof during a rain shower, diverting it away from the storage tank. This initial flow, known as the “first flush,” typically contains high levels of debris, contaminants, and pollutants that can compromise the quality of the stored water. By diverting this initial flow, the First Flush Diverter ensures that clean water enters the storage tank, reducing the risk of contamination and extending the storage life.

Design and Installation

A typical First Flush Diverter consists of a chamber or valve that separates the first flush from the clean water. The design and installation of the First Flush Diverter depend on the specific rainwater harvesting system, but it is generally recommended to install it at the edge of the roof, where the downspout meets the roof surface. A typical installation involves a 5-10% diversion ratio, where 5-10 liters of the first flush are diverted for every 100 liters of clean water entering the tank. This ensures that the First Flush Diverter is effective in capturing the initial flow of contaminants while allowing clean water to enter the storage tank.

Benefits and Advantages

The use of a First Flush Diverter offers several benefits and advantages, including improved water quality, longer storage life, reduced maintenance, and increased efficiency. By preventing contaminants and pollutants from entering the storage tank, the First Flush Diverter ensures that the harvested water is safe for use in irrigation, toilet flushing, and other non-potable applications. In addition, the reduced maintenance requirements and extended storage life of the First Flush Diverter make it a cost-effective solution for rainwater harvesting systems.