Welsh Revenue Authority allows taxpayers to submit applications for multiple dwellings relief online.
The questionnaire can be found here: https://www.gov.wales/amend-land-transaction-tax-return-claim-multiple-dwellings-relief-refund

It’s very important to note that Welsh revenue authority legislation surrounding multiple dwellings has changed as of January 2025.

Link to the legislation: https://www.legislation.gov.uk/wsi/2025/119/contents/made

—

New Land Transaction Tax (LTT) Rules in Wales – 2025 (Explained Simply)

The Welsh Government has now changed the rules on how tax is calculated when buying multiple properties in one transaction. This mainly affects people buying a home with an annex or multiple dwellings in one go.

What Has Changed?

Before the new law:

  • Buyers could combine two tax reliefs—Multiple Dwellings Relief (MDR) and Subsidiary Dwellings Exemption (SDE)—to pay less tax when buying multiple properties together.
  • This meant some buyers paid less tax than intended, even if they were not private landlords or developers.

Now, under the new 2025 law:

  • If you buy a main home with an annex (subsidiary dwelling) and qualify for SDE, you can no longer claim MDR on the same transaction.
  • This prevents double tax breaks in cases where buyers are only paying the standard residential tax rate.
  • However, if you are paying the higher tax rate (like investors or landlords), you can still claim MDR.

Who is Affected?

  • Homebuyers purchasing a main home with an annex—they will no longer get both tax reliefs together.
  • Landlords and property investors buying multiple dwellings at the higher tax rate—they can still claim MDR.
  • The change affects only a small number of transactions (about 100-120 per year).

Why Was This Changed?

  • The Welsh Government wants to close a loophole that allowed some buyers to reduce their tax too much.
  • It will also raise an extra £1-2 million per year to fund public services.
  • The new law makes tax rules fairer and clearer.

What Does This Mean for Buyers?

  • If you are buying a single home with an annex, you may now pay more tax.
  • If you are a landlord or developer buying multiple properties, your tax situation remains the same.

This change brings Wales closer to the tax rules in England and Northern Ireland, where MDR was abolished in 2024. The Welsh Government will continue reviewing MDR in the future.