Throughout the world, rainwater harvesting is a way of life; and in the U.S., it is rapidly growing in popularity as a simple and easy conservation method. Drought, limited resources and energy costs are driving the trend for rainwater harvesting based on the fact that about 70% of the water we use can be replaced with rainwater. Rainwater harvesting systems collect and use the water at the source, reducing energy needs for processing and movement as well as limiting storm water run-off.
The first component is the collection system. Water is typically captured from a roof, but it can also be collected from permeable pavement or a dry creek bed. Cleaner water leads to less filtering and maintenance.
Once water is captured, it is directed into the second component, a filtration system, prior to entering the storage vessel. There are a variety of filters available on the market. The Original Rainwater Pillow system uses a debris pad filter. The benefit of a pad filter is that the water is cleaned to a greater extent. The filter pad needs to be cleaned once or twice per year and replaced annually. The second type of filter is a screen which removes materials larger than the screen size. Screen filters are often on metal roofs because there are no asphalt granules that need to be removed. The screen filters are also self-cleaning.
The next element of a rainwater harvesting system is the storage tank. There are three types of storage vessels: below ground, above ground and horizontal pillows. In choosing the right vessel the user must consider both its planned location and cost. The Original Rainwater Pillow is designed to be installed in horizontal wasted space such as a crawl space or under a deck. The Pillows are custom built to fit the available space. Above ground tanks are simply installed next to the collection area and can vary in size as small as a rain barrel to many thousands of gallons. Lastly, there are underground storage tanks and systems. These can be either rigid tanks or crate systems surrounded by a liner.
Typical crawlspace installation
The final part of a rainwater collection system is the pump which is required to move the water.There are numerous pump sizes and capabilities from which to choose. The lower cost pumps must be manually turned on and off and will pump about 10 gallons per minute at 25 PSI. As prices increase, the options may include fully automatic demand pumps with sensors that can determine if water is available and which will monitor the system for leaks. In selecting a pump it is important to match the pump size with the anticipated water volume and use requirements.
Additional add-ons are available to maintain water levels, to flush toilets, roof washing, aeration and drinking water processing.
A basic rainwater harvesting system for hand watering irrigation can cost as little as $2,500, with upgrades, such as providing for toilet flushing, beginning at approximately $1,000. Of course prices will vary depending upon the specifics of your individual circumstances and needs.