Any black mold in your home deserves to be taken seriously, and the shower is where people underestimate it most. The dark growth on grout and caulking sits in a permanently damp spot, sheds spores into a small enclosed room you use daily, and scrubbing it puts those spores directly into the air you are breathing at arm’s length. Mold that has colonized caulking or grout also cannot be scrubbed out, the growth is inside the material, which is why it keeps reappearing no matter what product gets sprayed at it.
The bigger risk is what shower mold often signals: mold spreading to the ceiling or walls beyond the surround, growth returning within days, or a musty smell from inside the wall all point to moisture where it should not be, a leaking pan, failed waterproofing, or a plumbing leak behind the tile. That is a structural problem wearing a cosmetic disguise, and it grows quietly until someone opens the wall. Nonstop Restoration can tell you which situation you have, and the inspection is free: (403) 620-8489.