O fis Ebrill 2018 ymlaen, Awdurdod Cyllid Cymru fydd yn gyfrifol am gasglu a rheoli’r dreth gwarediadau tirlenwi a’r dreth trafodiadau tir – sef y ddwy dreth sy’n cael eu datganoli i Gymru. Byddant yn disodli’r dreth dirlenwi a’r dreth stamp sy’n cael eu casglu gan Gyllid a Thollau Ei Mawrhydi ar hyn o bryd.
From April 2018, the Welsh Revenue Authority will be responsible for collecting and managing landfill disposals tax and land transaction tax – the two taxes being devolved to Wales. They will replace landfill tax and stamp duty land tax, respectively, which are currently collected by HMRC.