The greatest misuse of water outdoors is to wash driveways, sidewalks, and gutters with a hose. The only commercially available product that eliminates this type of waste is a push broom. Lawn sprinkling and landscape irrigation often consume two to three times more water than is used indoors.
Water the lawn only when it needs it; if the grass springs back when you step on it, there is no need to water.
Water the lawn during the morning or evening to minimize evaporation. Do not water the lawn when there is a chance of rain or on windy days.
Infrequent, but heavy watering encourages the plant to develop a deep root system. Lawns only need about 1 inch of water per week in spring and fall, and 1 1/2 inches per week in summer.
Consider installing an underground sprinkler system. Sprinkler systems are a very efficient way to water your lawn. Adjust the sprinkler heads to water the lawn and not the sidewalk, driveway, or porch.
Landscape your lawn with native drought-resistant trees and plants. Place mulch around them to help retain moisture.
Raise mowing height to 2 1/2 inches from June 15 to August 30; avoid fertilizing in July and August, and aerate lawns in April and/or September to minimize compaction and improve rooting.
Wash your cars with a bucket of soapy water, and only use the hose for rinsing or take your car to a local car wash that recycles water.
Use a broom instead of the hose to clean paved driveways, sidewalks, and patios.