Irrigation

Irrigation is the artificial application of water to the ground surface in addition to what falls naturally as rainfall.

Since the mid 1990s irrigation has consistently been the largest use for freshwater globally.The use of recycled water for irrigation is widespread because water quality standards are less stringent where water is not for potable use or direct human contact. Irrigating land uses extensive amounts of water so there may be cost savings associated with using recycled water too. In the United States water used for irrigation represents 40% of all freshwater withdrawals and in 2000 amounted to 518 billion litres/day.

The two main irrigated environments are amenity/recreation areas (e.g. golf courses, public parks, and commercial landscaped gardens) and agricultural land (horticulture, crop production and grazing pasture for livestock).

The quality of water required for irrigation of agricultural land will depend on the crop type and whether the crop is eaten raw or cooked. In Australia recycled water is classified in one of four classes ranging from A - very high quality suitable for most purposes, through to D - lower quality water with more restricted uses.