Does she have food on a schedule, like eating morning/night... or is she free fed? I'm asking because if I offered my dog his food, and he didn't eat it - I would know something was wrong. Neither of our dogs are free fed, and if they didn't eat in the am/pm I'd be worried.
If she has food avaliable all the time, I probably wouldn't think too much of it.
As far as the water goes, I would keep an eye on her. If she's not acting herself, or if she continues to not drink I'd take her in. She could have gotten a drink while you wern't looking.