ceiling water stain cause 3

https://qqpipi.com//index.php/Is_That_a_Roof_Leak_or_AC_Condensate%3F_How_to_Tell_the_Difference

A ceiling water stain is usually caused by a leaking roof, burst pipe, or overflowing bathtub. When moisture soaks through drywall, it leaves a yellowish or brownish mark, often with a ring. Over time, the stain can grow and even cause the ceiling to sag, so it's important to fix the source promptly.