Longer grass keeps the soil cool, minimizing evaporation and conserving water. A lawn with insufficient water does not wear well. If you stop watering the lawn, do not cut the supply suddenly. Reduce the amount by a quarter of an inch a week to encourage gradual grass dormancy. On terraced lawns, water upper sections more than lower sections.
Moisture moves down.
Detergent waste water forms a soil surface crust that seals out oxygen and water infiltration. Oxygen reduction limits bacteria and inhibits lawn growth. If you decide to decrease lawn watering, you should not discontinue watering trees and shrubs. They cannot go dormant during the growing season. Trees and shrubs need moist, but not saturated, soil in order to grow well, resist insects, diseases and winter injury, and to produce flowers and fruit.