Water shortages and drought do not necessarily occur in the same places at the same time. Municipalities may experience water shortages when their water treatment system cannot keep pace with population growth in their service area.
Droughts occur when rainfall levels are below normal for an extended period of time. This can happen just about anywhere, but its effects are most notable where agricultural production or water availability for human consumption is affected.
During periods of drought or water shortages, reactions are often similar: non-essential water use is curtailed. Some of the major practices in the United States that are affected by water shortages, regardless of their cause, are: limits on washing cars, reductions of unnecessary watering of plants, especially outdoor plants, and re-use of water from sinks and showers, known as gray water. The latter is a more extreme example of a response that is becoming more mainstream as population growth continues and drought is experienced in areas of typically adequate rainfall, such as happened in the Southeastern United States in 2005-2009.
Water conservation practices such as rainwater harvesting, and water-wise gardening, sometimes known as xeriscapingTM, are a response to water shortages and drought.
Irrigation practices on golf courses and in residential and commercial landscapes can often be made more efficient by changing the method in which water is applied. For example, drip irrigation is more efficient than overhead sprinkler irrigation. Watering at night is more efficient than watering during the day. Gray water use for irrigation is possible to a limited extent.
