A sprinkler left on in one spot for more than the needed time wastes water. Set an alarm clock or timer as a reminder to move the sprinkler. Another sign of a dry lawn is grass that turns a dull gray-green. If only certain areas along sidewalks or driveways, for example are gray and the rest of the lawn is green, only water the dry areas. In good soil, less frequent, but heavier watering encourages a deeper root system and helps the lawn better tolerate hot weather.
Clay soil absorbs approximately one half inch of water per hour.
When the water starts to run off, turn off or move the sprinkler. Sandy soil needs watering more often and for shorter periods of time. Grassy areas on the sunny southern sides of buildings, on slopes, and areas near sidewalks and driveways need to be watered more often. Shady areas and northern exposures need to be watered less frequently. If you have an automatic sprinkler system, make sure it is not watering too long or too often.