Was your sod rolled into the existing soil base after it was laid so that good soil contact was made? New sod does typically needs to be kept moist, not wet, but unless the newly cut root surfaces have something to hang onto and grow into, water alone won't keep the sod alive very long, especially in the hot temps of August. See if you can easily pick up a piece or pieces of sod with your hand. If it comes up just like a (clean) piece of carpet then you need to call your contractor back out to install and roll it in properly.

To be sure, there is typically a period of some days/weeks after new sod is laid when planting stress is evident as shown by browning and wilting but this condition should pass after the first few weeks. On the other hand, brown doesn't necessarily mean that "new" sod is totally dead.

Think of cut flowers in a vase... the first few days, they look pretty good but after that, the flowers begin to fade and die because they're not getting nutrients or moisture.