Most units of property liable for NDR, called hereditaments, are included on rating lists held by billing authorities (the 22 principal local authorities in Wales).
Caiff y rhan fwyaf o unedau o eiddo sy'n atebol am dalu ardrethi annomestig, sef hereditamentau, eu cynnwys ar restri ardrethi awdurdodau bilio (y 22 o brif awdurdodau lleol yng Nghymru).