Short answer: Yes. Technically correct answer: Depends on the water. Hydrogen is an element defined by having 1 proton. However elements can have different numbers of neutrons and still be the same...
They are not really simlar:
The hydrogen atom consists of a single proton in its nucleus. If you add 1 neutron
you have the isotope Deuterium add a second neutron and you have Tritium.
Although...