Plumber came late afternoon. The fix was relatively simple. Getting the building to let him stay past 4:30 took the most time. Whatevs.

The drainage pipe was blocked up. If my system were set up right, then it would be a simple as popping off part of a T-joint and shooting some air in. Instead, there was no T-joint, just a 90-degree bend, which involved cutting and replacing, and then blowing the clog out of the way (likely pet hair, what a shock). So, no more drips and I can run the AC as much as I want. Yay! Also yay, instead of the couple thousand I was afraid of, the whole thing only cost me some aggravation, two hours from work, and $150.

So I should be set on water-related disasters for another three months.