Rainwater harvesting is an ancient technique enjoying a revival in popularity due to the inherent quality of rainwater and interest in reducing consumption of treated water. Rainwater is valued for its purity and softness. It has a nearly neutral pH, and is free from disinfection by-products, salts, minerals, and other natural and man-made contaminants. Plants thrive under irrigation with stored rainwater. Appliances last longer when free from the corrosive or scale effects of hard water. Users with potable systems prefer the superior taste and cleansing properties of rainwater.
Archeological evidence attests to the capture of rainwater as far back as 4,000 years ago, and the concept of rainwater harvesting in China may date back 6,000 years. Ruins of cisterns built as early as 2000 B.C. for storing runoff from hillsides for agricultural and domestic purposes are still standing in Israel (Gould and Nissen-Petersen, 1999).
Advantages and benefits of rainwater harvesting are numerous (Krishna, 2003).
-The water is free; the only cost is for collection and use.
– The end use of harvested water is located close to the source,
eliminating the need for complex and costly distribution systems.
– Rainwater provides a water sourcewhen groundwater is unacceptable or
unavailable, or it can augment limited groundwater supplies.
– The zero hardness of rainwater helps prevent scale on appliances,
extending their use; rainwater eliminates the need for a water
softener and the salts added during the softening process.
– Rainwater is sodium-free, important for persons on low-sodium diets.
– Rainwater is superior for landscape irrigation.
– Rainwater harvesting reduces flow to stormwater drains and also reduces
non-point source pollution.
– Rainwater harvesting helps utilities reduce the summer demand peak and
delay expansion of existing water treatment plants.
– Rainwater harvesting reduces consumers’ utility bills.