Usually caused by cracked plumbers putty or too much flex in the fiberglass tub due to lack of support Reseal or replace the shower drain by cutting a new hole for the drain flange using a drill and a drywall saw How to fix a leaky shower drain by tracing the water stain on the ceiling to the shower, take apart the drain and replace the cracked shower.
Shower drain leak repair - YouTube
A leaky shower can be more than an annoyance—it can lead to water damage, mold growth, and increased utility bills
Frustrated by a leaking shower
Save money & water damage The repair cost is about $30 for new parts Turn off the water supply Install the new drain assembly