It's true. Electricity needs some way to be conducted from one point to another. It needs something to carry it, or carry the electrical charge. Water itself is not a good conductor. Water molecules are satisfied electrically, and appear neutral to an electrical field or potential. They don't carry electrons, because they don't have any extra room for electron "riders", the ones that would be "conducted". To get conduction you need to have some ions in the water. That is: negative and positive molecules or atoms like sodium (plus) or chloride (minus) as when you dissolve salt in water. Once you have these ions, the electrical charge has a way to travel through the solution on these ions which greatly desire to have an extra electron. But with plain water, there is nothing for the electrons to "ride" on, so they can't go anywhere, hence there is no conduction.