While most humidifiers recommend using only distilled water, you can enjoy the Canopy Humidifier with any type of water. Tap water is totally fine to use, as the filter will catch contaminants from the water before it is evaporated.
With that in mind, the hardness of your water will affect how frequently you'll need to change your filter. The harder your water the more often you should order a Replacement Filter. You can learn how to determine whether or not you have hard water here, and how often to replace your filter here.