Apartments Sharing Leak

relatively new to the facilities management and maintenance field. always helped with around the house jobs but certain things end up being out of my realm of expertise. so here it goes.
i work and live in apartments in the cocoa beach area. two units are experiencing similar issues and they are also connected. units 1&2.
unit 1 has two bathrooms units 2 has 1. one of unit 1s bathrooms shares the waterwall with unit 2s. now here comes the strangeness for me. the leak in unit two is running along the exterior wall. the leak in unit 1 is along the molding and sink of the adjoining wall.

apparently based on what i have been told by one of the tenants is that these bathrooms have had issues before, they were both 'remodeled' and are now showing issues again. the one is wall and floor tile unit 2 which is the blue tile in the pictures the other which is drywall is unit 1.

as far as i can tell the leak is either originating from under the tub and running out of the bathroom in u1 and down the wall out towards 2 or there is a major break in the water wall. if that was the case i would imagine there would be sitting water most of the time. there is none. it could also be the drain line of the tub being cracked and seeping out which is why it isnt constant since they say they dont use the tub often(in u1). i have also read that there is a possibility of foundation failure allowing water in through the floor but the signs dont point to that for me because there are no loose tiles in either bathroom. could it be a roof leak.

sorry for the off the wall writing and i hope the issue is clear enough when you look at the pictures. the one directly nxt to shower that was obviously patched at one point is misleading because for me it looked heavily damaged but as far as i can tell it wasnt moist nor did it have any give it just looks like a poor patch. and insight would be greatly appreciated. look forward to working and speaking with people hear on this forum. i hope your experience and expertise can be shared and bestowed upon me as i further train and sharpen my skills.

thanks

Welcome to the site.
Is this a slab floor?
Are the tubs up against other rooms where access may be got to look under them?
Have you ruled out a roof leak, could be much distance from problem area?

Hey thanks for the quick reply I will try to answer your questions I believe it is a slab floor with tile on top. The tub in the bathroom discussed is butted against the adjoined wall. I have no idea goal would access under them but with my plumbers they may know and then a roof leak is on the list unfortunately but have NOT ruled it out

Around here in first floor slabs they often just leave a hole in the concrete for the drain plumbing and lay the pipe in gravel under the slab so a failure in the perimeter drain and high water table can lead to a fountain under the tub.
If you can do an attic inspection, you are looking for any water stains on the framing or wet insulation, any where even 10 or 15 ft away.
You said there were previous problems, any records of what was found or re-placed?

Not that I am currently aware of but I will definitely have to find out. The entire complex was Jerry built in the 60s and was all cast iron as far as I am aware. We acquired the property with very minimal information but I may be able to talk to previous owners and see about getting g that info. Couldn't hurt at the very least. So as far as the attic inspection if I don't have a crawl space or any type of access hatch is there a way of finding a problem strictly on the roof? Obviously other than a gaping crack or obvious obstruction. Any tell take signs to look for?

If you can get on the roof take picture of general condition and flashing and post that in the roofing section for opinions. Do the bathrooms have fans, pay attention to where that air goes.