#1 START EARLY
Plan your landscape ahead of time, so that new planting occurs in Spring. Plants require far less water to adapt in the Spring than during our scorching Summer months. Plus, this keeps you out of the heat!
#2 GO NATIVE
When choosing what to plant in your yard, consider native, drought-resistant species. They often require less water once established (here is AZ sometimes none at all) and aren't as maintenance-demanding.
#3 REDUCE YOUR LAWN
The average American household uses 320 gallons of water per day, 30% of which is typically devoted to outdoor use. More than half of this outdoor water is used for watering gardens and lawns. Consider reducing the footprint of your lawn, or eliminating it entirely - go with an attractive drought-resistant ground-cover that covers a large area and is mow-free! If you love the lush look and feel of grass, have your contractor install a premium artificial turf.
#4 SUPER SOAK IT
Roughly 1/3 of all water from sprinklers can evaporate during the heat of the day and even more in Summer. To reduce evaporation, give your plants fewer and heavier soakings. If you require use of sprinklers for turf areas, limit their use to early mornings.
#5 CAPTURE RAINWATER & RECYCLE GREYWATER
Capturing rainwater during monsoons or harnessing grey water from your home provides a free source for landscape irrigation. These types of systems can be easily installed and incorporated directly into your irrigation system.
#6 INSTALL DRIP IRRIGATION
Drip irrigation systems deliver water right to the root of your plants and are an efficient alternative to "bubblers" and sprinklers used in older landscapes. The use of drip-type systems typically use 20-50% less water than conventional bubbler / sprinkler systems and can your water consumption by 30,000 gallons per year. Don't forget to install a timer and educate yourself on its functions to maximize efficiency from season to season.
If your site is not extremely flat, and you have an elevation difference of over 5 feet in the areas you are looking to irrigate, ask your landscape contractor to install "pressure compensating emitters" instead "flag emitters" throughout these areas. These types of emitters discharge water at a very uniform rate under a very wide range of water pressures, and will reduce unnecessary runoff from mounds, berms, and terraces within your landscape. They are a bit more expensive, but you'll be getting a return on your small investment in the long run.