Rainwater harvesting is a process dating back to ancient times. It uses building roofs and other man-made surfaces to catch and redirect water into a holding container. The water can be used for irrigation or consumption for both animals and people. Today, the "back-to-the-land" and green movements have brought back rainwater harvesting and it is becoming more popular than ever. Modern designs of rainwater harvesting projects usually utilize gutters on houses to move water into cisterns. Water is filtered and then used as water in home or gardens.
Advantage: Low Maintenance
One reason people of both developing and developed countries seek out rainwater harvesting systems is the relatively small amount of maintenance required to obtain free water for drinking and household use. Annual gutter, down-pipe and tank cleaning is needed. This is usually limited to removing leaves, dirt and other debris before the major rainfall season. Filters need to be inspected every three months or so and the tanks should be monitored for cracks. These low-cost tasks are simple to do for the average person with minimal skills.
Disadvantage: Unpredicatable Rainfall
Rainfall is often hard to predict and usually comes and goes. This is the main downfall of rainwater harvesting. Unless many large storage tanks are used, it can be hard to store enough water to get through dry spells. If an area has limited rainfall, depending on rainwater harvesting for all water needs is not recommended.
Sustainability is one reason rainwater harvesting has become more popular in recent years. It is an environmentally responsible way to landscape plants, garden and lawns. The presence of rainwater harvesting projects helps limit soil erosion, storm water runoff and surface water contamination. It is a step in local self-sufficiency, reducing the need to import water from unsustainable outside sources. In addition, it gives people a concrete lesson in water use and conservation, as they can plainly see how much water the local climate produces.
Cost is one factor slowing down the proliferation of rainwater harvesting projects. A new installation can cost anywhere from $200 to $2,000 or more, depending on the system's size and technology level. Like solar panels, rainwater harvesting setups do eventually pay for themselves, but can take anywhere from 10 to 20 years, depending on the system and rainfall.