Grasses that grow along the top of the soil may need shorter watering times but
several waterings. Grasses that form deed roots will need longer and less frequent waterings to get further into the ground where the roots need to develop, areas repairing from damage, or being overseeded will need more water for the new growth to establish.
More water is needed in the spring when new blades are forming and the fertilizer needs to be watered into the root system.

All living organisms require water in some form or the other. Water for the plant system works similar to what it does for ours. Water carries food photosynthesized from the leaves to the roots and returns to the leaves carrying nutrients gathered by the roots from water in the soil. As we can become dehydrated so can grass plants and the water absorbed is used as the cooling system and in the return of oxygen into the air.
The majority of all water used by the plant enters at the root level and the excess is given off in the form of vapor by the leaves. Germination and cell development needs water. Too much water in the ground causes the roots to become overloaded and the lack of oxygen makes them start to deteriorate and in some grasses cause iron deficiency. That is why most of the recommendations are for well draining soils. Lawn grasses love water but not to be water logged.
Grass plants are adapted to the different climates and weather conditions in nature. Seeds germinate, grow into seedlings, mature, set seed and in the winter or drought conditions go back into dormancy until the conditions are favorable again. We have decided that we like grass as our permanent ground cover for lawns, parks, athletic fields, anywhere and everywhere. Since that time we have coaxed and bred and produced the different varieties of the different species into almost year round service. This has been achieved through the ability to water more than any other practice. Extreme cold weather is the only factor in having a year round lawn almost anywhere on the continent.