It is 5 o'clock and I get a text from a tenant in the downstairs unit, "Mike, we have a steady drip in the bedroom coming from upstairs.". I respond, "On my way".
When I arrived at the property, I called the upstairs tenant and learn they are out of town until weeks end. I let them know of the situation and they told me to let myself in to their apartment to find the cause. I searched the apartment and all the areas where plumbing ran looked normal and dry.
The downstairs apartment has plaster ceilings and the drip happened to be coming from a seam of where a support beam meets the ceiling. Coincidentally, right above this seam is where plumbing work was performed 2 years ago. To me, the obvious cause is one of the joints in the newly installed plumbing is leaking.
After calling every plumber and contractor in my small city, my ace contractor luckily calls back and can swing by!
We looked everything over, twice, and agreed the new plumbing must be the culprit. We head upstairs and prepare to remove the trim, flooring and sub-flooring, and upon doing so the ace notices a steady stream coming from the bed room. We follow the stream back only to find the condensate from the AC unit is dripping into the house (Yes, the upstairs tenant leaves the AC on for their cat while they are out of town). We adjust the AC unit so it is not leaking inside, wipe down the floor and call it a day. I was relieved that we didn't have to tear apart the apartment!