If the vet ruled out infections then it's probably a behavioral or stress issue. Dogs don't just change their habits overnight for no reason, so think about what happened that week - moving house, new pet in the home, change in routine, maybe you were away more than usual? Even the July heat can affect their behavior, older dogs (yeah, 5 years is when they start feeling their age) can have control problems when it's too hot. In the meantime, clean the areas where she peed thoroughly - and I'm talking real enzymatic cleaner, not ammonia that smells like urine and invites her to do it in the same spot again. Uric acid doesn't go away that easily.
Then, back to basics: increase daily walks by at least a couple, especially after meals and before bedtime. Confine her to a smaller space when you can't watch her - like just one room - because dogs tend not to pee where they sleep and eat. If she can curl up comfortably on the couch and pee without consequences, why would she stop? Reward her generously when she pees outside, with cuddles and treats. Don't yell at her if you catch her - dogs don't understand punishment after the fact and she'll just get scared, making the anxiety worse.
If it keeps happening after a couple weeks of this, go back to the vet and ask for a second opinion or if they can recommend a behaviorist. Sometimes these problems have simple solutions, but if it's not stress or habit, it could still be something medical that the first checkup missed.