You've probably washed all the nitrogen away with all that water. Fertilize it,
and cut the watering back to not much more than once a week.

Are you sure watering once a week would work in high-temperature Zone
9? We're hovering around 100 degrees most of the summer and I have to
hand-water dry spots frequently as it is. :/

My question is what does your sod sit on?

I had the soil rototilled and amended with copious amounts of compost
before planting. The native soil is a bit on the clay side, but not
terribly.

Kay, I'll check the condition of my grass blades when I get home
tonight. I use a mulching blade, which I had sharpened at the
beginning of the mowing season.

What species is/are in the lawn? What have the temperatures been like, day and night?

The lawn is a blue fescue mix. The daytime temps are in the upper
90's, low humidity, with nights in the lower 60s.

Thanks for the input.

-Fleemo