Q: How much water should I give my new lawn to get it established?
A: Start your lawn on the weekend or when ever you have the time to observe your watering. The new lawn should stay moist all day (tip: look for telltale dark, moist soil) but should not have puddles over night to avoid creating mold. For sunny lawns water 30 minutes in the very early morning and, optionally, once more at 2 pm in the afternoon if it is very hot. For shady lawns 20 minutes of water in the morning should suffice. Your Pearl's Premium seed should take 1-2 weeks to sprout. For the first 3 weeks after sprouting, water daily. Then for the next several weeks, water every other day. You do not need to water on a rainy day.

During the first year in very hot weather water deeply once a week with an inch of water to help encourage deep roots.  Once established, if you water, water infrequently but deeply. After the first year you should seldom (perhaps once a week during drought) or you never need to water aagain. Under extreme heat conditions, yyou can let the lawn go dormant. It will green up again with rain. 

Pearl's Premium is very good grass, but it is not miracle grass. You MUST water it for the first month and address compacted soil or very acidic soil with a little lime to get the grass established. No watering in the first month and it will fail. If you can’t reliably water, set up sprinklers with a timer from a home improvement store.