Mains water in Norfolk (England) is supplied by Anglian Water (Essex & Suffolk Water in the Great Yarmouth/Lowestoft corner); typical hardness: Hard to very hard, ~200 to 300 mg/l CaCO3. Water quality is regulated by the Environment Agency · Ofwat · Drinking Water Inspectorate.
Sources: Anglian Water (Essex & Suffolk Water in the Great Yarmouth/Lowestoft corner)