Deionized water vs distilled water – DI water is as pure as the distilled water or even purer.
Pure water does not conduct electricity. Any impurities, like salts, in the water enable it to conduct electricity. When salts are dissolved in water, they separate into different electrically charged atoms called ions.
That being understood, also know that introduction of corrosion residue into that water, may indeed make it conductive. So keep it clean and always disconnect power before working on anything electrical.
Introduction of about 5% contact cleaner into your water can help clean. Or clean the board with the cleaner then rinse with the pure water.
This guide can give you a lot of information:
Electronics Water Damage