Larry, I would agree with Larry.
Have to agree also...don't know where Rockin' at, maybe he's finally getting his unit waxed.
Can reach my tank from the storage compartment, behind the panel, luckly easier to get to. Was in the water tank area over the weekend, annual sanitize the tank time and installing two water alarms in that area. Might also check vent line next to the fill tube Larry indicated also. Was interesting to watch the tank fill up, might not do it next time.
You asked if the 'city fill' and 'dump line' were connected, on my units there not. The only thing common with either would be the vent line for the tank but any loose connection will leak. One thing I noticed was how 'nasty' the vent tube was....it can and will collect some water over time....for a clear tube, it was almost grey/black. When the tank was empty, bleached it also and got it cleaned as well. The way the tube was routed allowed water to sit in the low spot and not drain. Not the case now. Slightly off topic but...