Generally, the landlord is responsible for maintaining the structural integrity of the property. This includes addressing issues arising from inherent building defects, such as faulty waterproofing, leaking pipes within the walls, or inadequate ventilation systems that were part of the original construction. If the persistent humidity and mold growth are a direct result of such a defect, the remediation cost falls on the landlord.

However, as a tenant, you are responsible for maintaining the property in a clean and hygienic condition. This includes routine cleaning to prevent mold that results from daily activities. Merely running an exhaust fan is often insufficient; it must be verified that the fan is actually venting to the outside and is powerful enough for the room’s volume. Wiping down wet surfaces after showering is a critical tenant responsibility.

Given that the black mold is spreading from the shower corner—a classic trouble spot—this strongly suggests an underlying moisture issue. The creeping nature indicates it is likely more than just surface condensation. We highly recommend a professional inspection to determine the root cause. Our certified inspectors at Saniservice use moisture meters and thermal imaging cameras to identify the source definitively, which is crucial for determining liability.

Do not attempt to remediate this yourself with bleach, as this will only temporarily remove the visible stain and not address the hidden moisture problem, allowing it to return. For a definitive assessment and to understand your rights, it is best to get a professional evaluation.

For immediate advice or to schedule an inspection, please call us at 800-MOLDS (800-66537) or email hello@saniservice.com.