Mae Asiantaeth y Swyddfa Brisio (VOA) yn gyfrifol am brisio pob eiddo annomestig at ddibenion codi Ardrethi Annomestig (NDR).  Mae rhestri ardrethu newydd yn cael eu llunio a’u cyhoeddi fel rheol bob pum mlynedd.  Roedd ailbrisiad i fod i ddigwydd yn 2015.  Er hynny, penderfynodd Llywodraeth Cymru ohirio’r ailbrisiad tan 2017 yn dilyn penderfyniad gan Lywodraeth y DU i ohirio’r ailbrisiad yn Lloegr.
The Valuation Office Agency (VOA) is responsible for valuing all non-domestic property for the purposes of charging Non-Domestic Rates (NDR). New rating lists are usually compiled and published every 5 years. A revaluation was due to take place in 2015. However, a decision was taken by the Welsh Government to postpone the revaluation until 2017 following a decision by the UK Government to delay the revaluation in England.