Preheat the oven to 325°F.
Combine the water and condensed milk in a bowl.
In another bowl, beat the eggs until fluffy and light.
Pour a little of the condensed milk mixture into the eggs and mix well.
Add the remaining condensed milk mixture to the eggs, and stir in with the salt and vanilla.
Spoon the mixture into 8 ramekins or a 2-quart baking pan.
Put the ramekins or baking pan into a larger pan and pour water into the larger pan to come up ½-inch.
Cook in the oven for an hour (if using ramekins) or an hour and 40 minutes (if using a baking pan).
Let the Amish custard cool completely, then sprinkle with nutmeg and serve.