What could have caused this apartment flooding?

I had this problem last year when what was thought to be a water leak from the bathroom was really a leakage from a heater value.
Out apartments are heated through water pipes throughout each apartment.
I had to remove all furniture from the bedroom as they ripped up a corner of the wet carpet and had a plumber come in and solder the pipe again plus other work to fix the problem.
Two weeks of a foul smell from that leakage and whatever they used to attach the pipes?
I had to sleep in the living room with all the bedroom furniture piled against the wall..really inconvenient.
No compensation for me , but perhaps now thinking on it I should had demanded a motel room be paid by there insurance?

Possibly a leak im the pipes that wasn’t noticed right away. They will probably vacuum the carpet with a strong shop vac to get up as much water as possible & then run the fan to help in drying the carpet fully. They aren’t telling her anything out of fear she will sue for damages and they don’t want to give her any ammo

Stuck open toilet fill valve in the next room.

Water mixer valve, happened to us a few years ago. The mixer valve had a leak on the pressure side for the cold water. Inch of water in closet and bedroom. NOT cool.

The assisted living place isn’t taking care of the problem?

It could be something in the wall, plumbing related, or above the ceiling, or it could be water got out of her shower onto the floor and it seeped through the wall.

Does her shower have a curtain? Not placing the curtain well during the shower can allow excessive water to land outside of the shower area. If it has sliding doors, if the doors are not closed in the correct direction the water can get out too.

Is there an apartment above her? It could be from the bathroom above not closing their shower well while showering, and water is landing on the floor.