Poor ventilation, damaged grout or caulk, plumbing leaks and surfaces that remain damp for long periods can all contribute to recurring mold.

Scrubbing may remove visible mold while leaving moisture or mold growth beneath porous grout or damaged wall materials, mold remediation expert Cadence DeNoto told Martha Stewart. "No amount of scrubbing offsets a steady drip."

Soap residue, body oils and dust can also provide nutrients for mold. Even when bathroom surfaces appear dry, grout and nearby materials may retain moisture for hours.

Wet bath mats, towels and loofahs, inadequate ventilation and a dripping showerhead can further keep parts of the bathroom damp between showers.

Clean visible mold properly

Apply a suitable grout cleaner or mold-removal product according to the instructions on the label, Good Housekeeping recommends. For persistent spots, gently scrub with a non-scratch sponge or grout brush.

Rinse the shower thoroughly afterward and allow all surfaces to dry completely. However, removing visible mold alone is unlikely to solve the problem if the underlying source of moisture remains.

Surface cleaning is not sufficient for total mold removal. Photo from Pexels.

Reduce moisture after every shower

Good ventilation is one of the most effective ways to prevent mold from returning. Mold remediation expert Vanessa Van Holland recommends running the exhaust fan before or as the shower begins and keeping it on for another 20 to 30 minutes afterward, or until the bathroom and shower surfaces are dry.

Ideally, the exhaust fan should vent moisture outside the home. Leaving the shower curtain or door partly open can also improve airflow and speed up drying. Wet towels, bath mats and loofahs should be hung in places where air can circulate around them.

Dripping showerheads should be repaired because even a small, continuous leak can keep one area damp throughout the day.

Repair damaged grout, caulk and leaks

Because grout is porous, it can absorb water and take a long time to dry. Regular cleaning and periodic resealing according to the manufacturer's recommendations can help limit moisture penetration.

Cracked, peeling or deteriorated caulk should generally be removed rather than repeatedly scrubbed or covered with another layer. The area should be completely dry before new mold-resistant silicone caulk is applied.

Homeowners should also inspect loose tiles, slow drains, failed seals and plumbing leaks if mold repeatedly appears in the same location.

A persistent musty odor, soft drywall, bubbling paint, stains outside the shower or mold that quickly returns after cleaning may point to a larger hidden moisture problem.

In such cases, the underlying area should be inspected by a qualified professional before repainting or applying new caulk.