The value of every home in England is being reassessed to calculate new council tax payments.
The BBC's local government correspondent John Andrew explains how the process works.
What does revaluation mean?
When the council tax replaced the poll tax in 1993, homes were placed into one of eight property price bands - from A to H - based on the value of the property in April 1991. The system works so that those in the top band pay three times as much council tax as those in the bottom. The "middle" Band D - normally quoted as the average band - pays one and a half times Band A. Since then, prices have rocketed and this revaluation is about updating the values last taken 14 years ago.
But it is important to remember that this is not an exercise in raising more money. The total amount raised in council tax across England will remain roughly the same. The exercise is about how that burden is shared between properties of different values.
How will the exercise be carried out?
In 1991 properties were checked largely by estate agents and valuers. This time technology will play a much bigger role - with fewer site visits to individual homes. The exercise will be conducted by the Valuation Office Agency (VOA) - an arm of the Inland Revenue. They will use computer modelling technology to speed up the process, using sales information and data about number of rooms, floor area and the age of properties.
Although the same system has been used in the USA, Australia and many parts of Europe, it has never been applied on such a big scale before. The VOA says it will improve consistency.
Does the fact my home has more than doubled in value since 1991 mean I will automatically go into a higher band?
No, it depends whether your house has gone up by more or less than the average. In simple terms, if all our homes had gone up by the same percentage since 1991, we would all stay in the same band. All you would have to do would be to change the price label on that band. But in the real world, some houses have increased in value more than others.
Our nearest guide is in Wales, where revaluation has already taken place. There, some 58% of homes have stayed in the same band. Around a third of all homes have gone up by one band or more - and some, just over 8%, have actually gone down. But in property hot spots, far more homes have gone up the bands - nearly 64% in Cardiff, 52% in Wrexham and 44% in the Vale of Glamorgan. Ministers have stressed, though, that Wales has different council tax bands and it would be misleading to suggest the same sort of movement across bands would happen in England.
When will I learn what band I will be in and can I appeal if I think the decision is wrong?
The Valuation Office should be allocating properties to bands in the summer of 2006, with draft valuation lists being made available from September next year. You will be able to appeal if you think your banding is wrong, but not until April 2007.
Will we have a new council tax system in place by then?
Almost certainly, yes. At the moment Sir Michael Lyons is conducting a review into local government taxation which will report towards the end of this year. One option for reform is to make the tax more progressive across the property values by adding new price bands at the top and bottom.
In Wales, they have already added a ninth "Band I" for the highest-priced properties where households are charged three and a half times as much as those in the bottom Band A.
There is also speculation that he may recommend a system of "regional" price bands to reflect the big difference in prices between one area and another.