Possibly a dumb question, but have you checked the pressure relief valve inside the heater cabinet to make sure it's not popped or leaking? That would release water into the heater cabinet, which could then follow any line coming into or out of the cabinet to a lower point, then dripping. Just a thought, but very easy to check. The pop off valve is immediately behind the control panel on the left side of the cabinet after you remove the access door. Good luck.
2015 Legacy SR340 360RB
2014 Jeep Wrangler Unlimited Toad
Gigi, Poppy and Sadie Lady...On the road, but not full time!