Cadastral Income Belgium Explained

The upfront costs of buying a Belgian property — registration duties, notary fees, mortgage deed taxes — get most of the attention. What catches many expat buyers off guard are the ongoing annual obligations: a property tax levied every year you own the asset, and an obscure calculation called the "cadastral income" that drives it. For non-resident investors and expats who retain property in their home country, this same cadastral income system also has a direct effect on their Belgian income tax rate, even when Belgium has no right to tax the foreign property itself.

What is cadastral income?

The cadastral income (revenu cadastral in French, kadastraal inkomen in Dutch) is a notional rental value assigned to every property in Belgium by the Federal Public Service Finance. It is not the actual rent the property generates — it is a theoretical annual income figure calculated on the basis of normal market rental values. Crucially, Belgium's cadastral income figures are based on a 1975 reference index. They have never been systematically updated to reflect real market rents, which means they are significantly lower than actual rental values in today's market.

The cadastral income serves two functions:

1. It is the base on which the annual précompte immobilier (property withholding tax) is calculated
2. It is used as a proxy for taxable "immovable income" for Belgian tax residents who occupy their own homes or own domestic investment properties

The précompte immobilier: Belgium's annual property tax

The précompte immobilier (onroerende voorheffing in Dutch) is the annual property tax levied on all real estate in Belgium, payable by the owner each year regardless of whether the property is rented out or owner-occupied.

The calculation starts with the indexed cadastral income — the base 1975 figure multiplied by an annual government index coefficient. For the 2025 and 2026 tax years, this coefficient is set nationally. The regional and local governments then apply their own percentage levies to this indexed figure.

The result is that the effective annual property tax rate varies significantly by municipality. Brussels typically produces higher annual property tax bills than comparable Flemish municipalities due to the high additional municipal centimes charged by the Brussels region and its 19 communes. Walloon municipalities also vary considerably.

As a rough order of magnitude, expect to pay annual property tax of between 0.5% and 1.2% of the property's market value, depending on location and property type. The actual bill is based on the indexed cadastral income, not on market value, but this range captures the typical effective burden.

Exemptions and reductions: Many Belgian municipalities offer reductions for the first five years of homeownership for certain buyer categories, and regional policies can provide partial exemptions for energy-efficient properties or for buyers meeting income thresholds. Your notary can advise on municipality-specific benefits.

Who is responsible for the précompte immobilier?

From a legal standpoint, the registered owner on January 1 of the tax year is liable for the full year's property tax. In practice, Belgian property sale contracts typically include a pro-rata clause: the seller pays the proportion relating to their ownership period, and the buyer reimburses their share at the signing of the acte authentique. Check the terms of the compromis de vente carefully — this adjustment should be explicitly stated.

Cadastral income and Belgian income tax for residents

If you establish tax residency in Belgium after purchasing your home, the indexed cadastral income of your primary residence directly enters your Belgian personal income tax calculation — but only at a 40% markup of the indexed figure, and it is then available for deduction against certain credits. In practice, for most owner-occupiers of their primary residence in Belgium, the effective income tax treatment of the primary home is neutral.

For investment properties owned by Belgian tax residents, the situation differs. The actual gross rental income is not taxed directly. Instead, the Belgian government taxes a notional rental income: 60% of the property's indexed cadastral income on a dwelling that is let to private tenants for residential use. This notional figure is often dramatically lower than the actual rent received, making domestic property investment tax-efficient for Belgian residents.

The foreign property trap for expat buyers

This is where the cadastral income system becomes genuinely complex — and financially significant — for international buyers.

Prior to 2021, Belgian tax residents who owned property abroad were taxed on the actual market rental value of that foreign property (if letting) or a presumed rental value, which was typically far higher than the cadastral income used for domestic properties. The European Court of Justice ruled this discriminatory, and Belgium responded with a 2021 legislative reform.

From 2021 onwards, Belgian tax residents who own foreign real estate must declare it, and the Belgian Federal Public Service Finance will assign a notional cadastral income to that foreign property based on its current market value. This removes the discriminatory double standard — but it creates a new administrative burden and a financial consequence that surprises many expats.

How it affects your tax position:

Although Belgium cannot directly tax the income from a foreign property if a double taxation treaty is in place (most of Belgium's major tax treaties prevent this), the assigned cadastral income from your foreign property is used to determine the progression effect (réserve de progressivité). This means:

• Your foreign property's notional Belgian cadastral income is added to your Belgian income for the purpose of determining your marginal tax rate
• The higher the assigned foreign cadastral income, the higher the tax bracket that applies to your Belgian salary and other Belgian income
• The foreign income itself is then exempt — but the presence of foreign property has already pushed more of your Belgian income into a higher marginal bracket

Practical example: An expat living and working in Brussels, earning €80,000 in Belgian salary, retains an apartment in London valued at £450,000. Belgian authorities assign a notional cadastral income to that London flat. Although Belgium does not tax the London flat's rental income (under the Belgium-UK tax treaty), the notional cadastral income pushes more of the expat's Belgian salary into the 50% marginal rate. The net effect is a higher Belgian income tax bill each year simply from owning property in another country.

The higher the value of foreign property held, the more pronounced this progression effect becomes. For expats planning to retain a primary residence in their home country while purchasing in Belgium, modelling this effect carefully before completing the Belgian purchase is advisable.

Non-resident property owners: the 2026 shift

Foreign buyers who purchase Belgian property as a non-resident investment without establishing Belgian tax residency face a different set of obligations.

Previously, non-resident owners could often avoid filing a Belgian non-resident income tax (NRIR) return altogether. Belgian law provided that non-residents with annual taxable Belgian immovable income below €2,500 were not required to file. Non-residents who financed their Belgian property via a mortgage could deduct mortgage interest from their gross rental income (or notional rental income), routinely suppressing taxable income below the threshold.

Effective the 2026 assessment year (covering income year 2025), the federal interest deduction for non-primary residence properties has been permanently abolished. There is no transitional period or grandfathering for existing loans. The abolition removes the tool non-residents used to keep their Belgian taxable immovable income below the €2,500 filing threshold, pushing thousands of foreign property owners into the Belgian tax reporting system for the first time and compressing net rental yields on existing buy-to-let investments.

Non-resident investors acquiring Belgian property from 2025 onwards should factor this change into their yield calculations from day one.

What to declare and when

Belgian tax residents must declare the cadastral income of all their Belgian properties annually on their personal income tax return. Foreign properties acquired from 2021 onwards must also be reported to FPS Finance for cadastral income assignment.

Non-resident owners with taxable Belgian immovable income above the applicable threshold must file the non-resident income tax return (déclaration à l'impôt des non-résidents / aangifte in de belasting van niet-inwoners) annually.

For a full picture of the ongoing holding costs, tax obligations, and regional annual tax rates relevant to your specific situation as a foreign buyer in Belgium, the Belgium Expat Property Guide covers both the purchase and post-purchase tax landscape in detail.

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