Which of the following is a common source of indoor moisture leading to mold growth?

Leaks and flooding are recognized as primary contributors to indoor moisture, creating the ideal conditions for mold growth. When water intrudes into buildings due to plumbing failures, roof leaks, or natural flooding, it can saturate materials like drywall, wood, and carpeting. These damp environments become conducive to mold proliferation, as molds require moisture to thrive.

While extreme cold temperatures and poor air circulation can indirectly relate to mold issues, they do not directly introduce moisture. Extreme cold can cause condensation if warm air interacts with cold surfaces, but it doesn't generate moisture on its own. Similarly, poor air circulation can lead to stagnation and may trap moisture, but without a source of water like leaks or flooding, it cannot create the conditions necessary for significant mold growth. High levels of sunlight may help to reduce moisture and inhibit mold development, as sunlight has a drying effect.

Therefore, leaks and flooding stand out as the most common and direct sources of indoor moisture leading to mold growth.