4,294 hectares of empty building land in Luxembourg: what is it, and where is it?

Luxembourg still has 4,294 hectares of undeveloped land zoned for housing, according to Note 32 from the Observatoire de l'habitat (the national housing observatory; July 2023, 2022 data). The figure has been doing the rounds for three years, but it raises a naive question that is usually dodged: what exactly is this land, fields, forests, gardens? The answer, backed by the notes and reports themselves: land that is already ready, located where demand is strongest, and held mostly by private individuals who have no pressing reason to build.

“Building land” is not a field waiting to be rezoned

The term is misleading. The 4,294 ha counted by the Observatoire are not farm plots or woodland in the green zone that would have to be reclassified before anything could be built. They are plots already designated as building land in the municipalities' general development plans (PAG), and in just two categories: residential zones and mixed-use zones. Housing can be built on them today, without amending a single plan.

This inventory is not an estimate. It comes from the Raum+ programme, run by the Observatoire de l'habitat and LISER together with the Department of Spatial Planning (DATer), which since 2004 has cross-referenced aerial photographs from the Administration du cadastre et de la topographie (the land registry), the digitised cadastral map (PCN) and the municipal PAGs.

That precision changes the debate. To those who argue for extending the built-up perimeters, the Raum+ data offer a finding that the spatial planning minister of the day acknowledged publicly when presenting the study.

There is no need to enlarge the building perimeters. The conclusion of this analysis is quite striking.

According to the government, the potential lying inside the existing building zones is enough to cover the country's housing needs for decades to come. LISER has translated it into units: up to 161,500 homes, according to Antoine Paccoud's estimate taken up in Note 32, while the theoretical need calculated by STATEC is in the region of 6,000 homes a year. What such a supply would do to prices is the subject of another article; what remains to be understood is why this land never gets built on.

4,294 ha

Four families of land, four timelines for mobilisation

The Observatoire classifies each plot according to what has to be done, administratively, before a first stone can be laid. Four very unequal families emerge.

Family of land	Mobilisation timeline	Share of potential
Baulücken (infill plots)	Short term: a simple building permit	~33%
“New neighbourhood” zones (PAP NQ)	Medium term: specific development plan to be drawn up	~27%
Deferred development zones	Long term: deferral lifted by the municipality	~14%
Other (mixed-use zones, public facilities)	Variable; 75% of mixed-use zones usable for housing	~26%

Infill plots: a third of the potential, ready to build

Baulücken, or infill plots, account for roughly a third of the potential. This is the simplest case: an empty plot between two buildings, in an already built-up neighbourhood, with road, water, electricity and sewerage at the plot boundary. The Observatoire speaks of “net availability” and of land that can be “mobilised in the short term”: a building permit is all it takes, with no specific development plan. The Observatoire's successive notes put these infill plots at between 618 and 941 ha, depending on the year and the perimeter used.

So the obstacle is neither technical nor regulatory. It lies in ownership. According to the Observatoire's analysis report on the owners of Baulücken, 75% of these plots belong to private individuals and only 6% to public bodies. And when Raum+ asks the municipalities about the owners' intentions, they estimate that only 60% of them wish to build or sell. The rest hold on to their plot, sometimes as a garden, often as a store of value.

New neighbourhoods: larger, slower, more concentrated

The second family, about 27% of the potential: land classified as a “new neighbourhood” zone, subject to a specific development plan (PAP NQ). These are larger plots on the edge of the built-up area, mostly meadows or waste ground. A PAP has to be drawn up, approved, and the land then serviced: the Observatoire deems them mobilisable in the medium term. It is also the family where ownership is most concentrated: these large plots are frequently held by the biggest landowners and by property groups, who keep them in their portfolios. The structure of that ownership, documented in Note 32, is the subject of a separate article.

Deferred zones and the rest

Deferred development zones, around 14%, are plots the municipality has deliberately put on hold: building land on paper, but whose development is postponed until the municipal council decides otherwise. Their horizon is the long term. The balance, about 26%, brings together mixed-use zones and zones for public facilities. It should not be written off: the Observatoire estimates that 75% of the area of mixed-use zones can accommodate housing.

Of 4,294 ha, then, a third can be built on immediately, a little over a quarter requires a development plan, and the fraction actually frozen by a public decision is limited to 14%.

A third of the reserves is already sealed

Second misunderstanding: the idea that mobilising this land would mean concreting over the countryside. In July 2023, when presenting the Raum+ update, the government specified that around a third of the areas counted, close to 1,900 ha, had already been artificialised. These are urban and industrial brownfields and areas due to change use: former industrial sites, abandoned retail parks, car parks, buildings slated for demolition.

~1,900 ha

The spatial planning portal defines a brownfield as land that has “lost its function, its purpose” and that “can be repurposed”. Building on these areas entails no additional consumption of soil: what has already been sealed is simply reused.

The same argument holds for infill plots. Filling a gap between two houses creates neither a new road nor a new network; it reduces sprawl and eases the pressure on farmland beyond the perimeter. For anyone concerned about soil and biodiversity, densifying the inside of the building zones is the cheapest route. The 4,294 ha are not at odds with the country's environmental objectives; if anything, they are their precondition.

Farmland inside the building zones, and a tax exemption

Part of the reserves, on the other hand, really is under cultivation: some plots classified as residential or mixed-use zones are still farmed or planted with vines. Nothing forbids it. But their value no longer has much to do with the yield of a meadow. According to STATEC, cited in Note 32, the price of building plots rose by 136.5% between 2010 and 2021, against 107.4% for homes under construction. An owner who farms a building plot thus sees it appreciate every year without breaking ground. The Observatoire's analysis report no. 19 (October 2025) records a fall of around 15% in land prices in 2023-2024, which wipes out only a fraction of that rise.

This is precisely the situation the land mobilisation tax (IMOB) is meant to correct. Bill 8082, tabled in 2022, was split in July 2025 after twenty-two formal objections from the Conseil d'État (the Council of State): part 8082A carries the property tax reform and the IMOB, while the tax on vacant homes was hived off. From the committee stage in July 2025, the text exempted land already used for existing agricultural or wine-growing activities, outside localities of particular interest for spatial planning. Improof.lu criticises this exemption: a significant share of building land would thereby escape the IMOB.

The government amendment of 12 November 2025 confirms the direction. It exempts from the IFON (the new property tax) and from the IMOB any land used, in the first tax year, for existing agricultural or wine-growing activities. The Conseil d'État delivered its opinion on 3 February 2026. As of 2 July 2026, the bill was still in committee, with no vote in plenary, and its entry into force is now expected around 2028.

In other words, the tax instrument designed to shift farmland out of its status as a store of value exempts it, and will not bite in any case before the middle of the next decade. The details of land taxation and the OECD's recommendations are covered in the article Who owns Luxembourg's building land.

Where the land is: where demand is strongest

One last preconception: that this land is lost somewhere deep in the Oesling, far from the jobs. The data say the opposite. The potential is concentrated in the most expensive and most sought-after municipalities in the country.

Luxembourg City first. According to the Observatoire's Note 22 (land potential 2016), the capital had 335 ha of land available for housing, or 11.8% of the national potential. It is at once the most expensive municipality in the country, €11,569/m² in the first quarter of 2026 according to Immotop.lu, and the one holding the largest stock of land in waiting. Around it, the Centre belt and the South: Niederanven, Strassen, Käerjeng, Sanem and Dudelange are among the municipalities with the largest available areas.

335 ha

This geography matches that of actual construction, as counted in the Observatoire's note on residential development (October 2024), reported by Le Quotidien.

Territory	Homes built 2004-2022
By planning region
Centre agglomeration	24,972
“Endogenous” municipalities	22,131
South region	16,386
Nordstad	1,784
Most active municipalities
Luxembourg City	9,238
Differdange	2,160
Sanem	1,903
Esch-sur-Alzette	1,878
Mamer	1,251
Hesperange	1,189

The national spatial planning programme designates sixteen development and attraction centres (CDA), meant to absorb the bulk of growth. Together they hold 27.9% of the available land, or 793 ha (Note 22, 2016 data). But the distribution is highly unbalanced: Luxembourg City alone accounts for more than 42% of that total. The other fifteen CDAs share the rest, some thirty hectares each on average, barely more than the national average of 27 ha per municipality.

The paradox of the North

The north of the country illustrates the reverse. Land there is markedly cheaper, but the jobs are elsewhere. According to the prices by canton published by the Observatoire de l'habitat, a flat under construction sells for €11,793/m² in the canton of Luxembourg against €6,718/m² in the North; a house costs €1,265,000 on average in the canton of Luxembourg, 78% more than in the North. An available hectare in Niederanven or Strassen is therefore not worth a hectare in Wiltz, neither in price nor in its effect on the shortage: it is the empty plots of the Centre and the South that carry the weight.

Immovalu's data confirm this gradient. The median asking price for sale currently stands at €8,140/m² across all listings, with wide gaps between municipalities; prices municipality by municipality can be consulted on the Towns page.

Summary: 85% of the potential can be mobilised without obstacle

One last piece is missing: the share of land that is genuinely usable. Raum+ distinguishes plots that can be mobilised without legal or physical obstacle from those subject to constraints, such as flood risk or difficult topography. According to the government (November 2021), 85% of the potential can be mobilised directly; the remaining 15% require preliminary studies.

Criterion	Share of potential
Nature of the land (Observatoire de l'habitat, Notes 22 to 32)
Residential and mixed-use zones of the PAGs, already building land	100%
of which serviced infill plots, no PAP required	~33%
of which “new neighbourhood” zones, PAP to be drawn up	~27%
of which deferred development zones	~14%
State of the ground (government, Raum+ update, July 2023)
Already artificialised: brownfields, sites to be converted (~1,900 ha)	~33%
Mobilisability (government, November 2021)
No legal or physical obstacle	85%
Subject to constraints (flooding, topography)	15%
Ownership of infill plots (Observatoire, analysis report no. 1)
Private individuals	75%
Public bodies	6%

Not a question of land, but of will

Back to the opening question. The 4,294 ha are neither fields to be rezoned nor forests to be cleared. They are building land by right: a third serviced and available on a simple permit, a third already artificialised, 85% free of any physical or legal obstacle, and concentrated in the capital and its outskirts, where prices are the highest in the country.

Neither area, nor geography, nor regulation explains the shortage, then. What remains is the decision not to build. It rests with private owners, who hold the great majority of this land and who, year after year, benefit from its rising value without lifting a finger; the tax designed to change that calculation has not been passed and will exempt cultivated land. A rational choice for each owner, a collective deadlock for the country. Who these owners are is the subject of the next article; what this deadlock costs those looking for a roof over their heads, that of the full dossier on the housing crisis.