Pure H20, in any of its allotropes, states, phases, and isotopes, is poorly conductive of both electricity and heat. Impurities, such as Fe or Cl in solution, increase conductivity at the cost of phase change temperature, pH, and reactivity.
If you attempt to pass electricity through water at low wattage, water has near infinite resistance. At higher wattages of DC, electrolysis occurs -- liberating ionic consitituents that have high potential energy and low activation energy (i.e. explosive). At higher wattages of AC, corrosion of the holding chamber occurs, which increases as the water increases in both pH and temperature. Depending on the contaminant, you can get a variety of dangerous, smelly, rusty, corrosive, and just plain nasty stuff