ceiling water stain cause 21

https://theceilingwaterstaincauseedge.ironwoodscope.com/posts/ceiling-water-stain-cause-roof-leak-ac-condensate-or-attic-condensation

A ceiling water stain usually points to a slow leak from above, like a busted pipe in the attic or a failing seal around a roof vent. Sometimes it's from a shower upstairs that wasn't properly caulked, and the moisture seeps through the subfloor over time. You'll often see brown or yellow rings forming, which get worse with each rainfall.