The answer to 'humidifier making noise' is that a noisy humidifier is often caused by a buildup of mineral deposits, worn components, or an issue with the water supply. Common symptoms include loud rattling, buzzing, or gurgling sounds coming from the unit.
To troubleshoot, first check the water tank and lines for any scale or debris buildup. You can try cleaning the tank and running a vinegar or humidifier cleaning solution through the system. If that doesn't resolve the noise, there may be a problem with the fan, motor, or other internal components that will likely require professional repair.