We get this question a lot as the grass starts to dry out as the spring rains lead into warm summer days. A general rule of thumb is to water your lawn with 1 to 1.5 inches of water per week. A great way to check if your lawn is receiving enough water is with a moisture probe, which you can find at any local hardware store. Godwin in Ada, Michigan has them stocked for you or Kingsland Ace Hardware in Cascade Michigan. There are different factors that influence irrigation frequency.
First being grass type
Different grasses require different amounts of water.
What we have in Michigan is mostly bluegrass, which goes dormant during drought and revives when rainfall starts again.
Another option would be tall fescue which has a deep root system and the highest drought tolerance of any cool season grass types
Second being Soil Type
Different soils absorb and retain moisture differently
Sandy: absorbs water quickly and needs less water more frequently
Loamy: Absorbs water evenly, without puddling or runoff
Clay: Absorbs water slowly and can cause runoff when water is applied to quickly to the lawn
Third being the lawns age:
A newly planted lawn will need more water than an established lawn. When watering a new lawn it is especially important to keep constant moisture to remain healthy and green.