An outdoor water-use restriction is a ban or other lesser restrictions put into effect that restricts the outdoor use of water supplies. Often called a watering ban or hosepipe ban, it can affect: irrigation of lawns car washing recreational uses such as filling swimming pools and using water slides planting of grass or control of the types of grass planted hosing down pavement areas Such bans may be put in place by local governments, or by a state government. In the latter case, local authorities often still can enact more restrictive measures. Such a ban is usually enacted during droughts, to preserve water for essential uses such as drinking and flushing toilets, as well as for firefighting. If there is a water main break, or a problem with a water tower or other reservoir, a ban may be enacted on a very local and temporary basis. Bans that control water and plant uses can be permanent. Greywater recycling is becoming a necessity due to shortages in freshwater supply, an increase in populations with its associated food supply, and economic development.