The effect of water on the properties and nanostructuring of the prototypical choline chloride: ethylene glycol deep eutectic solvent is studied using a combined experimental and theoretical approach. The reported results showed large hydrophilic character of the solvent, which is based on the ability of water molecules to be hydrogen bonded to the different components of the eutectic in a efficient way. The effect of water on the studied fluid is largely dependent on the concentration range but the properties of the eutectic solvent can be maintained up to reasonably large water content. Therefore, the water content in these solvents may be used for tuning and controlling their properties but maintaining properties and features.
