Normal water conducts electricity due to dissolved salts . Pure distilled water is poor conductor of electricity . So the more the salts and impurities in water the better conductor of electricity it will be . So salt water wins . read more
Saltwater is a good conductor of electricity because it is an electrolyte solution. Substances such as salts, acids and hydroxides that also are electrolytes can conduct electric current. Saltwater is a mixture that consists of water and sodium chloride. read more
There are so few of these (100 parts per billion in neutral distilled water) and their mobility is quite low (as the dissociated proton is almost always hydrogen-bonded to a water molecule to form a large and fairly heavy hydronium ion that will tend to hydrogen-bond to other water molecules), so the conductivity of pure water is also very low. read more