The overall charge of water is zero. A molecule of water has a total of 10 protons, which are positive, and 10 electrons, which are negative.
A molecule of water is made up of three components: an oxygen atom and two hydrogen atoms. Oxygen has eight protons and eight electrons. A single hydrogen atom has one proton and one electron. A molecule of water therefore has a total of 10 protons and 10 electrons giving it an overall neutral charge.
However, the uneven distribution of the three atoms results in parts of the molecule having different charges. The oxygen part of the molecule has a partial negative charge. Each hydrogen part has a partially positive charge. This separation of charge of the molecule is termed polarity.