Rainwater harvesting is the collecting, transfer, and storage of rain for later use. There are several advantages to these systems such as less stress on municipal sewer systems, less pollution of water systems, and free water for the homeowner.
Although, water is abundant and cheap in many areas, it is becoming more and more expensive and scarce in other parts of the world.
In many areas, watering a garden or washing a car is not allowed at times but, if you collect free rainwater, you can use it for those purposes.
These systems are even required by law in some countries such as Bermuda and the U.S. Virgin Islands.
There are different types of systems to meet the needs of most homes and businesses. For homes, water runs off of the roof during rains and into a gutter system. The gutters transfer the water to downspouts which deliver it to the ground. The simplest method is a rainwater barrel. These barrels are placed under the downspouts and the rain is stored in them. They usually have a spigot towards the bottom where a garden hose can be connected. If you do not like the look of a big barrel sitting at the corner of the house there are more modern options available.
Other types of rainwater harvesting systems use large tanks that are buried in the ground. They can be a concrete vault or tanks made of polypropylene, metal, or fiberglass. These tanks are usually sized to meet the needs of the home/garden during the dry season. The latest innovation is a modular storage system called the "Rainwater Hog" which includes stylish tanks that can be placed in a variety of ways. They can be buried, attached to the home or a fence, or even used as a decorative part of the landscape. The capacity of these systems can easily be customized and can also be changed easily when the needs of the home/garden change. This water can normally be used for watering a garden or for laundry and toilets in the home. With filters and purification, the water can also be used for drinking. In areas with hard water, the rain can actually be better for these things than the water from the city.
The latest innovation in rainwater harvesting is a flexible tank called a rainwater pillow. This is like a large bag that can hold from 1000 to 200,000 of water. The rain goes into the gutters of the home and then is delivered to a reservoir mounted on the side of the home. This reservoir contains a filter to keep debris out of the pillow and an overflow line to allow excess water to escape after the pillow is full. Then the rainwater is delivered to the pillow through a pipe. The water is removed from the pillow and sent to a pump which can be connected to a garden hose and sprinkler system, etc. The pump raises the pressure of the water to where it is useful. A remote control is used to turn the pump on and off and water is delivered to where you need it.