For the first 8 to 10 days, water two or three times daily, but only for 5 to 10 minutes. Avoid overwatering, which may wash away the seeds. Once the grass sprouts, water once a day for 15 to 30 minutes. It's typically best to water in the morning, when there's less evaporation. Avoid watering in the evening; it can lead to fungal diseases.
Tip: If you're having an automatic sprinkler system installed, be sure it's equipped with a rain sensor that prevents it from operating during rainstorms.