Skip to main content

How properties are valued for Council Tax

Posted by: , Posted on: - Categories: Council Tax

[English] - [Cymraeg]

Council Tax bands are based on the open market value of a property - the price a home could have been sold for - at a fixed point in time.

This is known as the antecedent valuation date (AVD). The date used is set in law, and it’s different in England and Wales. 

  • In England, the AVD is 1 April 1991 
  • In Wales, the AVD is 1 April 2003 

Each Council Tax band covers a range of property values. This is why homes of different values are placed in the same band. For example, band C in England will be given to properties which would have sold for £52,001 to £68,000 on the AVD. 

We consider three types of evidence when working out Council Tax bands – sales, banding and settlement evidence. In this blog, we’ll look at each type of evidence and how it helps us make decisions and the weighting (that is, the relative importance) we give to each type of evidence.

Read more about how we value properties built after the AVD.

Sales evidence 

To decide which Council Tax band is right for a property, we first look at the price properties actually sold for around the AVD. This is called sales evidence. 

Sales evidence is the most reliable form of evidence, and we give the most weight to it. 

Our starting point is to find sales evidence on the ‘subject’ property (the property we’re allocating the band to). The sale must have been close to the AVD – 1991 in England and 2003 in Wales – for us to be able to use it as evidence. If this is not available, we then look at how much other properties in the area sold for at that time. These properties do not need to be exactly the same as the subject property, but they must be similar enough for us to compare. 

We compare each sale to the subject property, adjusting the price to reflect differences like size and location. This helps us to work out the value of the subject property, which then determines its Council Tax band. 

We do not consider house price data from free house price or house price index websites as a good form of valuation evidence.

This is because price indexing tools can be unreliable as they generally use data from wide geographic areas and draw on a wide range of different property types and recent sales prices.

This means that they do not give an accurate estimate of the open market value of a property as at the AVD.   

Banding evidence 

We always try to find sales evidence first, as this gives the closest estimate of the price a home could have been sold for. But if none is available, we look at banding evidence. 

As all properties are valued at the same date, we consider the bands already allocated to similar properties. This helps us to understand the pattern of banding for properties in the area and ensure that the band we apply is consistent with others. 

Settlement evidence 

When we look at the bands of similar properties, we give more weight to those that have been challenged and a decision has been made to change the band (this is what we mean by settlement).

This is because our initial decisions are tested during the challenge process, so the resulting Council Tax band carries more weight than a band that has never been challenged. 

We give the most weight to decisions made at Valuation Tribunal.

At a Tribunal, an independent panel considers all available evidence before deciding on the right band for a property. The panel also looks at previous valuation decisions. 

Next are Council Tax bands that have been settled through an agreement. This is when a challenge or proposal has been made, and we have agreed a change to a band. 

If similar properties have had their challenges withdrawn or we haven’t changed the band following a decision, then we’ll also consider this in our assessment.  

We welcome your comments about this blog below but cannot discuss individual cases. Please do not share any personal information. We will not be able to publish any comments that include personal details.

Please direct all queries about individual cases to our contact form.

[English] - [Cymraeg]

Sut mae eiddo yn cael eu prisio ar gyfer Treth Gyngor

Mae bandiau Treth Gyngor yn seiliedig ar werth eiddo ar y farchnad agored – hynny yw, y pris y gallai cartref fod wedi ei werthu amdano – ar adeg benodol.

Gelwir hyn yn dyddiad prisio rhagflaenol (sef ‘antecedent valuation date’, neu AVD). Mae’r dyddiad a ddefnyddir wedi’i osod gan y gyfraith, ac mae’n wahanol yng Nghymru a Lloegr.

  • Yn Lloegr, yr AVD yw 1 Ebrill 1991
  • Yng Nghymru, yr AVD yw 1 Ebrill 2003

Mae pob band Treth Gyngor yn cwmpasu ystod o werthoedd eiddo. Dyma pam mae cartrefi â gwerthoedd gwahanol yn cael eu gosod yn yr un band. Er enghraifft, yn Lloegr, rhoddir ‘band C’ i eiddo a allai fod wedi’i werthu am bris rhwng £52,001 i £68,000 ar yr AVD.

Rydym yn ystyried 3 math o dystiolaeth wrth gyfrifo bandiau Treth Gyngor – gwerthiannau, bandiau, a thystiolaeth o setliad. Yn y blog hwn, byddwn yn edrych ar bob math o dystiolaeth yn ei dro a sut mae’n ein helpu i wneud penderfyniadau. Byddwn hefyd yn edrych ar faint o bwys a roddir i bob un o’r mathau hyn o dystiolaeth.

Tystiolaeth o werthiannau

Er mwyn penderfynu pa fand Treth Gyngor sy’n iawn ar gyfer pob eiddo, byddwn yn edrych ar bris werthiant gwirioneddol pob eiddo tua adeg yr AVD. Gelwir hyn yn ‘tystiolaeth o werthiannau’.

Tystiolaeth o werthiannau yw’r dystiolaeth fwyaf dibynadwy, a rhoddwyd y pwys mwyaf iddi.

Yn gyntaf, byddwn yn ceisio dod o hyd i dystiolaeth o werthiannau sy’n ymwneud â’r eiddo ‘dan sylw’ (hynny yw, yr eiddo rydym yn dyrannu’r band iddo). Mae’n rhaid bod y gwerthiant wedi digwydd yn agos at yr AVD – 1991 yn Lloegr, a 2003 yng Nghymru – er mwyn i ni allu defnyddio’r gwerthiant fel tystiolaeth. Os nad yw hyn ar gael, yna byddwn yn edrych ar bris gwerthiant eiddo eraill yn yr ardal ar yr adeg honno. Does dim rhaid i’r eiddo hyn fod union yr un peth â’r eiddo dan sylw, ond mae’n rhaid iddynt fod yn ddigon tebyg i ni allu gwneud cymhariaeth.

Byddwn yn cymharu pob gwerthiant â’r eiddo dan sylw, gan addasu’r pris i adlewyrchu gwahaniaethau o ran maint a lleoliad. Bydd gwneud hyn yn ein helpu i gyfrifo gwerth yr eiddo dan sylw, ac yn pennu ei fand Treth Gyngor yn y pen draw.

Nid ydym yn ystyried data ynghylch prisiau tai o wefannau sy’n rhoi pris am eiddo yn rhad ac am ddim, na gwefannau mynegai prisiau tai, fel tystiolaeth o brisio dibynadwy.

Mae hyn oherwydd nad yw’r offer a ddefnyddir i fynegio prisiau yn ddibynadwy bob tro – a hynny gan eu bod, fel arfer, yn defnyddio data o ardaloedd daearyddol eang yn ogystal ag ystod eang o gwahanol fathau o eiddo a phrisoedd gwerthu diweddar.

Mae hyn yn golygu nad ydynt yn rhoi amcangyfrif manwl gywir o werth eiddo ar y farchnad agored ar adeg yr AVD.

Tystiolaeth o fandio

Byddwn yn ceisio dod o hyd i dystiolaeth o werthiannau yn gyntaf, gan ei bod yn rhoi’r amcangyfrif mwyaf cywir o bris y gallai cartref fod wedi ei werthu amdano. Ond os nad oes un ar gael, byddwn yn ystyried dystiolaeth bandio.

Gan fod pob eiddo yn cael ei brisio ar yr un dyddiad, byddwn yn ystyried y bandiau a ddyrannwyd eisoes i eiddo tebyg. Mae hyn yn ein helpu i ddeall y patrwm o fandio ar gyfer eiddo yn yr ardal, ac yn sicrhau bod y band yr ydym yn ei ddarparu yn gyson â’r bandiau eraill.

Tystiolaeth o setliad

Wrth i ni edrych ar fandiau eiddo tebyg, rydym yn rhoi mwy o bwys i’r rhai sydd wedi’u herio a lle bo penderfyniad wedi’i wneud i newid y band (gelwir hyn yn ‘setliad’).

Mae hyn oherwydd bod ein penderfyniadau cyntaf yn cael eu profi o dan y broses herio, felly mae gan y band Treth Gyngor wedi hynny fwy o bwys na fand sydd erioed wedi’i herio.

Rhoddwyd y pwys mwyaf i benderfyniadau a wnaed mewn Tribiwnlys Prisio.

Mewn Tribiwnlys, mae panel annibynnol yn ystyried yr holl dystiolaeth sydd ar gael cyn penderfynu ar y band cywir am eiddo. Bydd y panel hefyd yn ystyried penderfyniadau blaenorol ynghylch prisio.

Nesaf yw’r bandiau Treth Gyngor sydd wedi’u setlo drwy gytundeb. Dyma le codwyd her, neu le y cyflwynwyd cynnig, a gwnaethom gytuno i newid y band.

Os tynnwyd heriau ynghylch eiddo tebyg yn ôl, neu os na wnaeth ein penderfyniad arwain at newid band, byddwn hefyd yn cymryd hyn i ystyriaeth yn ystod ein hasesiad.

Sharing and comments

Share this page


  1. Comment by Margaret posted on

    Our house wasn't built until June 1991. How would you decide the valuation, please?
    Thank you.

    • Replies to Margaret>

      Comment by Valuation Office Agency posted on

      Good afternoon, all properties are banded according to our estimate of the value it would have achieved if it had existed and been sold on 1 April 1991 (in England) or 1 April 2003 (in Wales). We compare new-build property with similar property that sold at those dates, and with nearby property that is already banded.

  2. Comment by Ms Michele Middleditch posted on

    This is all very well BUT it does not cover re-banding owing to alterations/improvements made by previous owners. If a property is, say, in band C and it is "improved" I would like to know exactly what criteria you use to change the band. It cannot, for example be sufficient to say. "we estimate your changes will move your property into a different band". Exactly WHAT changes? What are the boundaries for instance for the square meterage of a property? What are the minimum number of bedrooms for any band? What is taken into consideration with regards to location? Or views? Or parking? Or size of plot? Does the type of property (e.g. detached, semi-detached, terraced house or bungalow; duplex, apartment block, converted flat/maisonette? Your explanation is not clear and certainly does not provide any transparency.

  3. Comment by Mr Frank W Budden posted on

    Only by researching myself do I find that my recently purchased property was subject to an improvement indicator (as a result of previous owners improvements) and this is why my property has been revalued. I was not made aware of this when I purchased.
    What is so disappointing is that when I made enquiries with the vauation agency, no considered response which properly answered my questions was provided. Standard responses with just contact information to other agencies was simply churned out. It's to be hoped that the agency can improve its service to a provide a clear understanding at the first stage. This would save time for the enquirer and the agency - who subsequently needed to revisit the issue.

  4. Comment by Jacqueline Mercer posted on

    Hi my property is exactly the same size has my neighbours house but they have a lower banding please can you tell me if we have been in the wrong banding for the past 41 years of living in our home.