Rainwater harvesting systems are used to gather and store rainwater. Harvesting rainwater can be used for many different purposes such as providing drinking water for humans and livestock and providing water for irrigation. Rainwater is normally harvested from the roofs, tents, or specially prepared areas of the ground.

In many countries, people depend on rainwater because it might be the most economical water source or it might be the only available water source. Most people harvest rainwater from roofs. In most cases, rainwater harvested from roofs is of good quality and do not require treatment before it can be used. However, some rooftops consist of materials that may cause the rainwater collected to be harmful.

There are many other different types of rainwater harvesting systems . Some are very simple while others are more complex. Almost all rainwater harvesting systems harvest rainwater from the ground or from a roof. There are ground catchment systems and roof catchment systems.

Ground catchment systems are used to harvest water from the ground in areas where there are no sources of water or where rainwater is not plentiful. Roof catchment systems use pipes and gutters to harvest rainwater from a roof. After a dry season, a rooftop will contain dust, bird droppings and other particles. When using roof catchment systems, the first amount of rainwater should not be used since that it might contain bird droppings, dust, pesticides or mosses. This is why it is advisable to treat rainwater collected from roofs before using it for drinking purpose.

The size of rainwater harvesting systems is very important in that they should be large enough to meet the water needs and demand through the dry season since that the rainy season does not last forever. The storage tanks should be large enough to store enough water. If the catchment area on the roof is not large enough, it will not be able to capture sufficient water to fill up the storage tanks.

Rainwater harvesting provides many advantages. It provides additional water sources to meet the requirements of the consumers. Untreated rainwater can be used for many different purposes such as flushing the toilet, bathing, and washing laundry. However, it is advisable to always treat rainwater before drinking it.