If it is Fescue, it isn't coming back on its own. You'll need to overseed and try to thicken it up before all the other weeds and invasive grasses take over.
Some sources say that Fescue is best planted when daytime temps reach between 60 and 75, which is true. However, we've had great luck with it through the middle of May where temps are 90+. It is a cool weather grass so the cooler the better. Still I've planted in June and had good germination.
As far as your soil goes, I'm sure that since its a construction zone, it's not the best. More important than nutrient value which is important but can be added topically with fertilizers, is the consistency and drainage of your soil. If it is compact, contractor fill, pure sand, or pure clay, you'll need to amend the soil. Get in touch with your local county extension agent or university agriculture program for help with this.
The best water saving advice I can give is to make sure you have the consistency and proper coverage of an
automated sprinkler system, that your soil is correct, and your slope is minimal to reduce runoff.
Steve