Is it legal to rent out a flat by the room: what the owner must check

Renting out a flat by the room is legal, but the key point is not just that the parties agree: it is necessary to check which legal regime actually applies to that contract. The Urban Leases Act expressly includes the partial letting of a room or space within residential letting when the main purpose is to satisfy the tenant’s housing needs. That means it cannot be treated as though any room rental were automatically a “special” contract or, conversely, as though it were always simply a standard residential tenancy without further nuance. The LAU considers a standard residential tenancy to be one involving a habitable building whose primary purpose is to satisfy the tenant’s housing needs, including the partial letting of a room or space in the dwelling.

What to check before renting by the room

The first check is substantive: what actual use will the tenant make of it? If the room is let for someone to live in it on a stable basis or as the tenant’s main home, it may fall within the residential regime. If, on the other hand, the contract is presented as temporary without a genuine cause or as accommodation/lodging, the legal approach changes. The law also distinguishes letting for a purpose other than housing and excludes contracts whose object is the accommodation or lodging of people. In other words: it is not enough to call the contract “short-term” for it to be so.

Step 1. Set out the purpose of the contract in writing.

1. If the tenant is going to use the room as a home, make it clear that this is a partial residential letting, to the extent that applies.

2. If a temporary arrangement is intended, the reason must be specific, real and capable of being proved.

3. Avoid generic phrases such as “temporary stay” if in reality there is no genuine temporary reason.

Step 2. Check whether the temporary nature is properly justified.

The current wording of the LAU requires short-term residential contracts to state expressly the reason motivating the tenant’s temporary move. In addition, that reason must be real and capable of being proved, and the burden of proving it lies with the landlord. If that reason does not exist or is not properly documented, the contract loses its temporary nature and becomes subject to the residential regime with retroactive effect from the date it was entered into. That is especially important when a room is let “by the room” in the belief that this avoids tenant protection under the law: that does not always happen.

A “fictitious short-term let” will not protect you if the use is residential

One of the most common mistakes is to draft a short-term contract for a room when the tenant is going to live there in the ordinary way. The law itself provides that the absence of a temporary reason duly set out in the contract removes that temporary nature. The owner should therefore check the reality of the situation before signing, not just the label on the contract.

The absence of a temporary reason duly set out in the contract will deprive it of its temporary nature and will mean it is subject to this title on the same terms as standard residential tenancy contracts, with retroactive effect from the time the contract was entered into.

Numbered steps worth following:

1. Check whether the tenant keeps their main home elsewhere.

2. State in the contract the reason for the temporary move, if there is one.

3. Keep any document that helps to prove that reason on file.

4. Do not copy a generic internet template without adapting it to the real case.

5. If in doubt, do not force a temporary arrangement that cannot later be sustained.

What to review in a room rental contract

Even if the flat is let by the room, it is worth setting out several points very clearly to avoid disputes:

1. Identification of the specific room and, where applicable, the common areas the tenant may use.

2. Agreed term and reason for the temporary nature, only if there is a genuine one.

3. Who may occupy each room and whether subletting or assignment is permitted.

4. Rules on use of the kitchen, bathroom, living room, cleaning and hours.

5. Allocation of utilities, expenses and method of payment, with clear documentation.

6. Basic inventory of the furniture or items provided in each room.

Also, when the flat is in a building owners’ association, do not forget to check whether there are bylaws or internal rules limiting certain uses. The Horizontal Property Act allows the association to regulate coexistence and prohibits annoying, unhealthy, harmful, dangerous or unlawful activities. It also provides that the owner must not compromise the safety, structure or configuration of the building. That does not mean that renting by the room is prohibited by default, but it does mean the owner must make sure that the specific use does not conflict with the building’s rules or with activities expressly forbidden. The association may set internal rules to regulate the details of coexistence and the proper use of common services and facilities.

Mistakes you should avoid as an owner

The biggest mistake is to think that room rentals fall outside the LAU simply because the whole dwelling is not let. The law specifically covers the partial letting of a room or space when the purpose is residential. Another common error is drafting a short-term contract without a real temporary reason. It is also wise not to mix imprecise concepts in the same document, such as “flexible rental”, “stay” or “room reservation”, when in reality stable use of a dwelling is being transferred.

Common mistakes:

- Using a short-term contract without justification.

- Failing to describe the let room.

- Not setting out in writing the authorised common areas.

- Failing to distinguish between a main home, temporary housing and accommodation/lodging.

- Not checking the association’s rules.

What to do if you want to rent with confidence

If you want to rent out a flat by the room and reduce risks, the most practical approach is first to sort out the legal classification and then the practical side of the letting. You can start with an indicative valuation of your property at /valoracion-vivienda-madrid, especially if you are also considering whether it would be more worthwhile to rent or sell. And if you would like to review the specific case before publishing the advert or signing, you can ask for help at /contacto.

Useful advice:

1. Prepare a specific contract, not a generic template.

2. Provide evidence of the reason if it is a temporary letting.

3. Keep written communication with the tenant.

4. Keep proof of key handover, inventory and payments.

5. If the building has strict internal rules, check them before offering rooms.

In short: yes, it is legal to rent out a flat by the room, but the owner must check whether the contract fits within residential letting, whether there is a genuine temporary arrangement and whether the building owners’ association imposes relevant limits. The key is that the reality of the use and the paperwork must match. If they do not, the label on the contract will not protect you.