Water will move through sandy soil much more quickly than it will in clay soils. If you don't know your soil type, watch for runoff as you water. If you see water running onto the curb, street, or sidewalk after 7 minutes of sprinkling, plan to water only 5 minutes per cycle. Repeat cycles every hour until you have applied enough water to wet your soil 8 to 12 inches deep. You may need to repeat your watering cycle as many as 5 times to achieve this. For heavy clay soils, you may need to apply about 1.1 inches of water to wet your soil this deeply. For sandy soils, you may only need to apply 3/4 inch to wet the soil to the same depth.
2) Water your lawn at appropriate intervals.
During the early and late parts of the growing season, you may water as infrequently as every 10 to 20 days! During the hottest part of summer, you may need to water every 2 days. Ideally, you should apply water only when the lawn grass appears slightly stressed. You can judge this by the slight change in color, or when footprints remain for longer than 5 minutes after walking over the grass.
3) Repair or replace faulty sprinkler heads.
Observe the operation of your sprinkler system once every other week. If you see any off-target sprinkling, try to adjust the head to apply water to your lawn, not the road or sidewalk. Sprinkler heads can accumulate pebbles or sand grains which decreases flow; clean them at least once a year.