40-50% Affordable Housing Reserve in a Sitges Housing Project

A protected housing reserve is the share of a new residential sector's techo (buildable floor area) that the plan must set aside for state-protected housing. Since 1 January 2026, art. 57.3 of the Llei d'urbanisme, the Catalan urban planning law, as amended by Ley 11/2025 requires plans to reserve at least 50% of techo in the transformation of suelo urbanizable (developable land) and 40% in suelo urbano no consolidado (urban land not yet fully developed). For a housing project in and around Sitges, this means part of the sector's floor area is sold at a regulated price, and that revenue loss has to be deducted from the land price.

What does Catalan law require for new sectors?

Art. 57.3 obliges plans (the POUM, or municipal urban plan, its amendments and revisions) to reserve for protected housing at least 50% of the techo of new residential use in the transformation of suelo urbanizable and at least 40% in suelo urbano no consolidado. At least half of the reserve goes to rental. Before the law, the figures were 40% and 30% (Decret llei 2/2025).

Which caveats change the picture?

First: the obligation falls on the plan, not on the licence of an individual house. For POUMs and amendments that received initial approval before the law entered into force (1 January 2026), the reserve is not mandatory under the transitional rule (third transitional provision, paragraph 1). How paragraph 2 works, on the two years from initial approval of a territorial or master plan, is for an abogado urbanista (urban planning lawyer) to decide.

Second: after Decreto-ley 6/2026 of 5 May 2026, the consolidated text of art. 57.3 keeps 50% and 40%, but exempts small and rural municipalities more widely.

Third: the techo of sectors where the derived plan and the reparcelación (land reallotment) project are already approved does not count toward the reserve (art. 57.4). For suelo urbano consolidado there are no percentages, but the plan may require protected housing in new multi-family buildings (art. 57.6 and 57.7); that is how Barcelona's quota works, see the article on the 600 m² threshold.

Sitges operates under a POUM that entered into force on 24 May 2006 (Ajuntament de Sitges). The reserve that the plan and its amendments set for a particular sector is shown in that sector's documents.

How does the reserve change project revenue?

Worked example, not a forecast and not data on a real project. Assumptions: 10 000 m² of residential techo, a market sale price of 6 000 €/m², and the protected share sold under the general regime at 2 913,18 €/m² (Generalitat, 2026). For simplicity, areas are treated as equivalent.

The table assumes the whole protected share is sold. The law requires at least half of the reserve to go to rental, and rental usually returns capital more slowly, so the real picture is more complex. The revenue loss is deducted from the land price before the offer, as described in the article on the VPO quota and the price of a housing project. VPO (vivienda de protección oficial) is Spain's state-protected housing.

What to check in a project with a protected share outside Barcelona?

1. The land class of the sector and how urbanizable differs from consolidado.
2. Which reserve is set, in which act of the plan, and in which units (techo, number of apartments).
3. The price regime and the protection period: whether such homes are sold, rented or transferred to the administration.
4. Whether the reserve is built in the same construction phase or pushed to the final phases.
5. Whether the plan and the licence require the protected part to be delivered at the same time as the rest.

These points go to the abogado and the arquitecto before the arras (reservation deposit contract) is signed. On land in this area: plots in Sitges and Sant Pere de Ribes and the DNPI project in Sitges.

When does this analysis not apply?

It does not apply to Barcelona, where different rules operate, or to a sector whose plan received initial approval before 2026: there the reserve may not apply. It also does not apply if you need a conclusion on a specific sector: that requires the plan documents, not general percentages. The calculation is not a forecast: it shows the size of the effect, not the price the market will pay. To test scenarios for your sector, use the calculator; the way we work with land plots is described on the development page.