Resources and Tips:
Watering: Austin lawns need about an inch or two of water per week due to the extreme heat in the summer. Try to use one long, soaking watering (rather than a shorter watering every day) to give your lawn its week's worth of "rain."
Water in the early morning. Watering in the evening invites disease.
Most grass is designed by nature to work around droughts by reducing growing activities when water is in short supply, so don't despair if your lawn isn't looking as grand as you wished - remember that the solution could be as simple as watering.
Go to the City of Austin's Page on Watering and other helpful tips.