In a blender or with a whisk, mix the eggs, milk, and water until smooth. Gradually add the salt and flour, then blend in the melted butter.
Refrigerate the batter for at least 2 hours, or overnight.
Heat a non-stick frying pan over medium heat and brush with melted butter.
Pour 2 to 3 tablespoons of batter into the center of the pan and tilt the pan to cover the bottom evenly. Cook for about 1 minute, or until browned on the bottom, then flip and cook briefly on the other side.
Cool the crêpes on a rack or plate. Serve as desired.