RVs and cabin cruisers are especially prone to persistent odors because they combine enclosed living spaces with conditions that encourage odor buildup. Limited airflow allows smells to linger, while moisture from condensation, plumbing systems, bilge areas, and ambient humidity creates an ideal environment for bacteria and mold. Soft materials such as upholstery, foam cushions, headliners, and wood panels readily absorb these odors and hold onto them over time. Heat further accelerates microbial growth, intensifying musty and sewage-like smells, and extended storage periods often make the problem worse by allowing odors to concentrate without ventilation.