If a customer with an irrigation system insists that you give them an actual predetermined schedule you should offer the following information.  First, in the spring, do not run the system until it is needed.  Very seldom do we experience spring droughts and they should inspect the lawn for signs that the lawn needs water before getting on a normal schedule.  When it comes time for consistent irrigating they should set their system to have each zone run for forty five minutes every three days.  Each section of lawn does not need to be watered every day and running a zone for ten minutes is a waste of water.  A deep dose of water every third day is good general rule for effective irrigation.

The system, as a general rule, should run in the hours around dawn.  Temperatures are normally coolest at this time of day and it is best for the lawn to not remain soaked during the nighttime hours.  It is commonly said that you should never water your lawn at night.  This is only true during times of high humidity when disease activity is most likely to occur.  Watering during the heat of the day is generally not a good idea simply because higher temperatures will cause the water to evaporate before it can soak into the root zone.