Properly watering a lawn is key to maintaining it in a healthy condition. Most lawn problems are either directly or indirectly related to poor irrigation practices. Failing to apply sufficient water will result in dry areas which will turn brown and ultimately die if left too long. On the other hand, excess water can lead to disease and lawn damage. As you can see, it is important to irrigate your lawn correctly.
A key to proper irrigation is learning to recognize the signs of a thirsty lawn. Turfgrass is a very interactive plant material, which immediately indicates its dryness by changing from its typical green color to a slightly blue-gray tint; closer inspection of the turf will show that it is somewhat limp as well. When dehydrated turf is crushed (e.g., stepped on), it will not spring back as a properly hydrated lawn would.
Usually a section of lawn that shows a need for more water will continue to be the first area to be identified as thirsty. This is the area that likely receives the least water due to irrigation inefficiencies and/or receives the most direct sunlight. This thirsty area should serve as the gauge to adjusting sprinkler time.