If it rains, don't water. Lawn Watering Tips Watering should start as soon as water stress is evident. Stress indications include footprints that remain for a long time after grass has been walked on. Lawns require at least an inch of water every week depending on the soil, grass variety, season and height of cut. Frequent, shallow watering leads to shallow roots.
Shallow roots lead to more rapid stress under drought or hot conditions.
Don't over-water your lawn. Wait as long as possible between waterings to allow the root zone to dry out, which encourages deeper roots and thereby drought tolerance. During the heat of the day, water is wasted by evaporation. Evening watering can encourage lawn diseases. Low soil water stresses desired grasses.