When it comes to watering lawns there are many different opinions on how long and how often to water.
How Often Should I water?
Depending on the weather and time of year lawns should generally be watered 2-3 times a week which is less often than most people water. Lawns should dry out completely in between watering to encourage root growth and reduce disease and fungus. If the lawn starts to get a grayish tint and the grass does not lift back up when you walk on it it needs more water.
How Long Should I water?
The secret is to water for longer periods of time allowing the water to soak deep into the soil which is what we want to achieve. The benefits are that it encourages the roots to grow deep which helps the grass be more healthy and drought resistant. Lawns should generally be watered 1-1.5 inches a week which would be a half inch per watering if watering 3 times a week. An easy way to measure this is to get something like a tuna fish can to place on your lawn while the water is going and see how long it takes to get the desired amount of water. You can then set your timer accordingly.
When Should I water?
Early mornings are generally best before the sun comes up this way the water wont evaporate as much and will be better used. Another benefit of early morning is that it will dry out quickly as the sun comes up so that you can still mow the same day it was watered.