About 45% of the mass of lunar soil is oxygen, locked into rock. Getting it out takes a great deal of energy and no water at all.

Every silicate mineral up there is built around oxygen atoms, so the raw material for breathing and for rocket oxidiser is underfoot everywhere, not just at the poles. Several proposed methods — molten regolith electrolysis, hydrogen reduction — have been demonstrated in laboratories on Earth. None has been tried on the Moon.