As a general rule, keeping your lawn healthy requires 1 inch of water weekly, including rainfall. Water once every 2 to 3 days in dry weather (about 1/2 inch at each application). If one or more inches of rainfall occur in a week, additional irrigation is not necessary. (Example: if 1/2 inch of rain occurs within a growing week, apply 1/2 inch by irrigation.)
Heavy clay soils will require less water and less frequent applications than sandier soils.
Water as deeply as possible without causing run-off. Water to supplement rainfall shortages only. Avoid fixed timer irrigation settings. Do not waste water by over watering; avoid standing water for any period of time.
To determine how much water you are applying, place gauge midway between the sprinkler and the end of the coverage and check water depth in the gauge after a planned length of time (approximately 1/2 hour), then calculate the total time needed to apply 1/2 inch.