The brutal temperatures we've been experiencing are a challenge for gardeners.  Even established trees and shrubs may perish due to the combined heat and drought. Any plants less than a year old will surely die without additional watering. Most garden experts advise watering plants twice a week and watering deeply enough to reach and saturate roots. Less frequent and deeper watering encourages stronger root growth more than daily, shallow watering. The best time to water is before 10am and after 7pm. Mulch also helps conserve moisture around the plants.
Per the Declaration of Covenants of Hidden Springs, each lot owner is responsible for maintaining his or her own landscaping in a healthy condition. So after the summer ends, any dead plants should be removed and replaced. But prevention is the best cure. Landscaping is an investment that increases the value of your property so it should be protected like any other investment. You may have to prioritize what your water based on what it would cost to replace, the length of time it would take to regrow to its present size/condition, or its intrinsic value to your property.  For example, you might decide to water trees and shrubs but not the lawn because the grass will regrow. Lawns can be kept alive with just one good soaking every couple of weeks or so.  It's worth more to water perennials (plants that live from season to season, year after year) rather than annuals (plants that grow for only one to two seasons and then die).