Is Tap Water a Heterogeneous Mixture?

According to Georgia Perimeter College, tap water is not heterogeneous. Heterogeneous mixtures have at least two substances, and viewers can see what is in it. Tap water is homogeneous, as homogeneous mixtures have at least two substances in them, but viewers cannot see them.

Heterogeneous mixtures look like mixtures, such as trail mix, chocolate chip cookies, spaghetti sauce and concrete. Heterogeneous matters can be separated by different physical means, such as filtering, sorting, heating, cooling, freezing, melting, settling and evaporation. Homogeneous mixtures appear to be made up of one substance, but if tested, they can be proven to be composed of more than one substance. In addition to tap water, some examples of homogeneous mixtures are salt water, sugar water, brass and cake batter.