"pure" water is only H2O so there are no solutes, because of osmosis, water will enter the red blood cell that does contain solutes until the cell and the surrounding environment (in this case the water) are iso-osmotic, this will never happen though because the water contains no solutes.
Sumer has come up with a great analogy for a presentation she is giving in her psychology class. The membrane encasing a neuron only allows some ions to pass in and out of its channels. And she is going to describe this cell membrane as a guard only allowing some patrons to enter and leave a controlled area.