Water is a natural environment for biochemical, geophysical, environmental, and many technological processes. Hence, understanding properties of water on a molecular level is a prerequisite for understanding how water influences and drives chemistry. Yet, despite a plethora of experimental and theoretical studies, water continues to puzzle scientists. In this contribution, we focus on the most basic property of water, that is, its electronic structure. The key element of electronic structure is the shapes and energies of molecular orbitals, which describe the states of electrons and ultimately determine chemical properties of a substance. Molecular orbitals can be probed by photoelectron spectroscopies, connecting theory with the experiment . An important question is how molecular orbitals are affected by the environment, that is, in which way a water molecule in bulk water differs from an isolated water molecule 7 . Because molecular orbitals are sensitive to the intermolecular interactions, their energies can also provide information about local solvent structure and its fluctuations.