Each dwelling is allocated to one of eight bands coded by letters A to H (A to I in Wales) on the basis of its assumed capital value (as of 1 April 1991 in England and Scotland, 1 April 2003 in Wales). Newly constructed properties are also assigned a nominal 1991 (2003 for Wales) value.
The government had planned to revalue all properties in England in 2007 (the first revaluations since 1993) but, in September 2005, it was announced that the revaluation in England would be postponed until "after the next election". At the same time, the terms of reference of the Lyons Inquiry were extended and the report date pushed out to December 2006 (subsequently extended to 2007). In Wales, tax bills based on the property revaluations done using 2003 prices were issued in 2005. Because of the surge in house prices over the late 1990s and early 2000s, more than a third of properties in Wales found themselves in a band higher than under the 1991 valuation. Some properties were moved up three or even four bands with consequent large increases in the amount of council tax demanded. Some properties were moved into new Band I at the top of the price range. Only 8% of properties were moved down in bands.
Between the wholesale revaluations, a major change to a property (such as an extension, or some major blight causing loss of value) can trigger a revaluation to a new estimate of the value the property would have reached if sold in 1991. If such a change would result in an increase in value, then re-banding will only take effect when the property is sold or otherwise transferred.