Is 1 hour too long to water grass?

Is 1 hour too long to water grass depends on sprinkler type, soil, and weather, but generally 1 hour is too long for fixed spray heads and may cause runoff, but appropriate for rotor heads and drip systems that apply water slowly. Fixed spray heads apply 1.5 to 2 inches per hour, so 1 hour would deliver 1.5 to 2 inches at once, which is more than weekly need and causes runoff and waste, especially on clay soil, so 15 to 30 minutes is better for spray heads. Rotor heads apply 0.3 to 0.5 inches per hour, so 1 hour delivers 0.3 to 0.5 inches, which is appropriate for one watering session, and many rotor zones need 45 to 60 minutes to deliver 0.5 inch. Sandy soil may handle 1 hour better than clay. Watering 1 hour daily would be too much, causing shallow roots and disease, but 1 hour once or twice a week for rotor zones is acceptable. So 1 hour is too long for spray heads but not too long for rotor heads, and frequency matters, with deep infrequent watering better than long daily watering.