“Water only once a week, but water deep” is the rule. A weekly soaking helps roots extend deeper into the soil, while frequent shallow waterings tend to lead to thatch, that unsightly web of dry brown runners just above the soil. Watering deeply can also prevent chinch bugs, a pest that tends to attach dried, stressed out lawns across the midsection of the country. To figure out how much water your lawn needs, take your soil type into account: sandy soils dry out faster, while clay soils hold moisture longer and don’t require watering as often.
For a newly seeded lawn, water every day for five to 10 minutes only. Your goal is to dampen the seeds without causing runoff that might wash them away or mar the surface with gullies. After the seeds sprout and the new grass is a half inch tall, water once a day for 15 to 20 minutes.Article from: https://www.hgtv.com/design/outdoor-design/landscaping-and-hardscaping/basic-lawn-care-tips