If some solute is dissolved in pure water, the solution has fewer free water molecules and the concentration (free energy) of water decreases, reducing its water potential. Hence, all solutions have a lower water potential than pure water; the magnitude of this lowering due to dissolution of a solute is called solute potential or is always negative. The more the solute molecules, the lower (more negative) is the ws. For a solution at atmospheric pressure (water potential) (solute potential) .