When, How Long & What Time?
Every day people ask me, "When, how long and what time of the day should I water?" These are excellant questions to ask your lawn professional. "When" is well, before it turns brown! I visit many home owners every day and notice light discoloring of their lawn. Another sure sign is when you notice foot prints in your lawn. When you see this, drag out the hose and sprinklers.
Early morning is the BEST time to water your lawn, and you'll want to give your lawn about 1 to 2 inches of water per week, either from your irrigation system or rainfall. Watering your lawn over night promotes diseases. A great way to find out how much water to apply is to invest in a rain gauge. This will not only measure the weekly rainfall your lawn is getting, it will also measure how much your watering. The goal you are trying to achieve while watering your lawn is to keep your lawns entire root zone moist, from the soil surface to 6 to 8 inches deep.
A typical lawn can infact survive eight weeks or longer with out water, of course it will go dormant and turn brown, but they will not die. When watering your lawn use your rain gauge to help you determine "How much" water to apply. If your lawn received 1.5 inches of rain in a weeks time, you'll need to make up the difference with your sprinkler system. You'll also want to measure how much water your sprinklers apply in a given amount of time. This will help you determine "How long" to water.
Watering your lawn pays off. You'll build a deeper, healthier root system which will give you a more resilient lawn.
Basic Rules OF Watering 
Moisten the root zone every time you water, usually with at least 1/2 inch of water.
Water deeply and infrequently, at least twice a week, 1/2 inch at a time.
Recognize the need.
Myths, Facts & Good Advice (From the Pros)
Myth: The best sprinklers are the ones that deliver the water the fastest.
Fact: True, but only if your soil can absorb the water.
Advice: Match your sprinkler's application rate to the soil's absorption rate. Watering slowly is best.
Myth: Brief, daily watering is most beneficial to my lawn rather than deep watering every other day.
Fact: False, watering deep every other day increases healthy, deep root growth.
Advice: Watch your lawn and wait for the first signs that it needs water. "Recognize the Need".
Healthy tips: (click on a topic to view)
Trust your lawn care professional (they might just know what they are talking about)