While it's possible to use tap water in your humidifier, it's generally not recommended. Tap water often contains minerals and other impurities that can accumulate in the humidifier over time, leading to mineral buildup and potential bacterial or mold growth. When the humidifier releases mist or steam, these microorganisms can be released into the air, potentially causing respiratory issues. Using distilled water is a better option as it is purified and stripped of all minerals and impurities. This can help to reduce the risk of bacterial or mold growth and improve the overall air quality in your home. If you must use tap water, it's important to clean your humidifier more frequently to prevent mineral buildup and bacterial or mold growth.