I just moved into a townhouse with the washer/dryer on the second floor. When I connected the washer, I must not have tightened the connection well enough, because water was spraying out at the connection point. I turned the washer off, but by this point the first floor ceiling had already begun gushing water through an air vent. Within a few hours, the drywall on the ceiling was mushy.
I’m wondering if it is possible that the drywall went soft that quickly and did that much damage from a washing machine connection not being tight enough. Any advice is greatly appreciated.
You definitely need to get rid of the drywall, if you haven't done it already. It can go soft quickly and then lead to other problems, like mold.
Generally my advice is that when a leak happens, poke a hole in the ceiling to give the water a place to drain out as quickly as possible. This actually prevents the drywall from swelling. Since that has already happened, it will need to be cut out and replaced. As far as mold is concerned, if the leak is stopped and the area dries fairly quickly, you probably won't develop mold. It take an ongoing high-moisture situation for mold to fester and grow.