People tend to use the brown spots and dry areas on the lawn to indicate when to water. I used to believe that the way to reduce water consumption was to design the sprinker systems so that it hit the dry spots with extra water.
Last year I took a new approach. I decided to go to each of the terminally dry spots and find out what is underneath them.
I took a pick and dug and dug into each of the dry spots. I've found and removed old root systems. In another area I found a really hard clay a few inches from the ground. In this case, i broke up the clay, mixed in mulch and closed the wounds.
The places I treated last year are nice and green this year. I tackled several other dry yesterday.
I think the secret to a healthy lawn in dry country is to concern oneself with the quality of the soil six inches down. IF the soil can hold water several inches down, then you can reduce water consumption by watering longer for fewer times.