Water is a good electrical conductor but not distilled water. Tap water, Sea water, rain water etc. conduct electricity as they consist of impurities; salts of Ca,Mg,Na which behave as charge carriers.
Sweat conducts electricity although it is mainly water, it still consists of lot of minerals, lactic acid, urea; in short, it is an ionic liquid (electrolyte)
Human body consists of 75% of water and also consists of many minerals and salts. So human body also conducts electricity.