This is a difficult question to answer in a simple manner. There are numerous factors that affect how much water is needed or how long we need to water to maintain proper plant health and the desired aesthetic appeal. Some of the factors to consider include:
These are only a few things to consider, but all of them have some influence on how often and how long we should water our yards. There are general recommendations that can be followed but we all need to use common sense in thinking about what we are doing. It is important to take time to learn about the soil properties and experiment a little on controlling and managing the water rather than just turning on the timer in April, set to water every day and turning it off in October.
There should be adjustments made throughout the season to reflect climate and weather conditions, and there should be adjustments made and different schedules created for various micro climate conditions in your own yard. Slopes, southern exposures and northern exposures will all have difffent water needs and all have best ways to water them.
To get specific information for your yard you may sign up for a water check, or you can do a self water check of your sprinker system. Click on the following links for information.