Black mould in a toilet bowl is primarily caused by moisture buildup.
Understanding the Root Cause: Moisture
Mould spores are naturally present in the air, but they require specific conditions to grow and colonize surfaces. The main trigger for mould growth in areas like a toilet bowl is the presence of sufficient moisture.
Factors Contributing to Black Mould Growth
Several factors contribute to the moisture buildup necessary for black mould to thrive in a toilet bowl, as noted in our reference:
- High Humidity Levels in the Bathroom: Bathrooms are naturally humid due to activities like showering and bathing. If this moisture isn't properly managed, it lingers in the air and condenses on surfaces, including the toilet bowl.
- Poor Ventilation: Inadequate air circulation means humid air stays trapped in the bathroom, preventing surfaces from drying out. This lack of ventilation significantly contributes to persistent moisture.
- Leaks or Cracks: Even minor leaks in the toilet itself (like a constantly running cistern) or surrounding plumbing can provide a continuous source of water inside or outside the bowl, creating ideal conditions for mould. Cracks in the porcelain can also trap moisture.
- Infrequent Use or Cleaning: A toilet that isn't used or cleaned regularly allows water to sit undisturbed for longer periods. This stagnant water, especially in the trap or around the rim, becomes a breeding ground for mould spores when combined with the factors above.
Essentially, any situation that keeps parts of the toilet bowl or its immediate surroundings consistently damp or wet provides the perfect environment for black mould spores to settle and grow.
