Except for maybe a private trailer park, you probably would not be able to find a potable water installation using steel pipe. The reason for this is that the service life for carbon steel piping will not be acceptable for most users. Most potable water applications use either ductile iron or PVC pipe. Piping within buildings may be galvanized steel pipe.
The European practices as well as the world practices are similar to the United States practices. However, the water usages are typically much lower in the rest of the world.
Some of the countries in Europe have their own standards. The UK and Russian Federation for example have their own standards.