We see water in a variety of ways. It may be colored by particles, the presence of bacteria, or by reflecting the world above its surface. Ice and snow may reveal a vivid internal blue. Water itself has an intrinsic blue color that is a result of its molecular structure and its behavior.
You need a clearer definition of the word colorless. I would define it as a substance that does not reflect or absorb photons along the VISIBLE light spectrum. It may indeed reflect /absorb photon energy at a wavelength that is not visible by the human eye, thus it will APPEAR to be clear.