Pure water does not conduct electricity. It is an insulator that has a high resistance and a low conductivity. Electrical current does not move through water easily.
Electricity does not flow through pure water, but it easily flows through impure water. In the environment, water dissolves many things; it is called the universal solvent. Even carbon dioxide in the air dissolves in water. Once these substances are dissolved, they carry the electricity through the water, especially if they form ions or charged atoms and molecules. It is the impurities in the water, not the water itself, that conduct the electricity.