Does the deposit rise every time the rent rises?
No, and this is the point most tenants get wrong. Your rent can go up once a year while you live in the flat, tracked to the official index, yet the deposit sitting behind that rent stays exactly where it started. The fianza on a home is one month's rent, paid when you sign and lodged with the authorities, and the law deliberately freezes it for a stretch.
That stretch is the mandatory term of your tenancy. During the first five years of the contract, or the first seven years where the landlord is a company rather than a private individual, article 36 of the Urban Leases Act says the deposit is not subject to updating. So even if your rent has climbed with the yearly increase across those years, nobody can ask you to add to the deposit in the meantime.
This is general guidance for renters, not legal advice. Deposit rules turn on the exact wording of your contract and your move-in date, so check anything specific with a tenant advice office, Incasòl or a qualified lawyer before you pay.
So when does a top-up actually become due?
When the tenancy is extended past that mandatory term. Once your contract runs beyond the five or seven protected years and rolls into a further extension, the freeze lifts. At that moment the landlord can require the deposit to be brought back into line with the rent, and, just as fairly, you can require it be lowered if the rent has dropped.
The trigger is the extension, not the calendar year and not the annual rent bump. Nothing happens to the deposit at each yearly increase. It is the renewal into a new period, after the guaranteed term, that opens the door to an adjustment. If your flat is still inside its first five years, a request to top up the deposit is not something the law backs, so it is worth knowing which side of that line you sit on before you agree to anything.
How much can the deposit go up to?
For a home, the deposit is topped up so it equals one month of the rent in force at the time of the extension. You do not pay a whole extra month. You pay the difference between the original one-month deposit you handed over and one month at today's higher rent.
A quick worked example, with round numbers for clarity:
| Stage | Monthly rent | Deposit held | You pay |
|---|---|---|---|
| Move-in | €1,000 | €1,000 (one month) | €1,000 at the start |
| Years 1 to 5, rent indexed up | €1,120 | €1,000 (frozen) | Nothing extra |
| Extension after year 5 | €1,120 | €1,120 (one month) | €120 top-up |
Two months, rather than one, is the figure for lets that are not housing, such as commercial premises. For your home it is one month, full stop. And this rule only concerns the legal fianza; a separately agreed extra guarantee follows its own limits.
Who pays the top-up, and is the money lost?
The tenant pays the difference, and no, the money is not lost. A deposit top-up is still your deposit. It sits as security for the same reasons the original did, and it comes back to you when you leave, minus any lawful deductions for unpaid rent or damage beyond normal wear. It is not an agency fee and it is not rent.
In Catalonia that money does not simply sit in the landlord's account. The landlord is legally required to lodge the fianza with the Institut Català del Sòl (Incasòl), usually within two months of signing the contract. When the deposit is topped up on an extension, the extra amount is deposited with Incasòl in the same way, and that updated figure is what feeds through when you eventually reclaim it. Our guide on getting your fianza back walks through how that return works.
What if your contract already runs longer than five years?
Some leases are signed for a long fixed term from the outset. For the portion of an agreed term that stretches beyond five years, or seven with a company landlord, article 36 hands the question back to the contract: the deposit is updated however the parties agreed to update it.
And if the contract is silent on the point? The law fills the gap with a sensible default: whatever you agreed for updating the rent is presumed to have been intended for updating the deposit too. In practice that means the annual index you already accept for the rent would carry across to the deposit. It is one more reason to read your update clause closely before signing, which our guide to reading a Spanish rental contract can help you do.
What to do when the deposit comes up
Work through it calmly rather than paying on the spot. A short, documented check protects both your money and your standing:
- Find your move-in date and count. If you are still inside the first five years, or seven with a company landlord, the deposit stays frozen and no top-up is due.
- Confirm a genuine extension is happening. The adjustment attaches to the renewal past the mandatory term, not to the yearly rent rise.
- Check the maths. For a home you owe only the gap between your original deposit and one month at the current rent, not a fresh full month.
- Ask about the Incasòl deposit. The top-up should be lodged with Incasòl, and you are entitled to know your deposit is registered there.
- Read your update clause if your term already runs past five years, since the contract, not the default, may govern the increase.
If any of it feels off, a tenant advice office or the Ajuntament housing service will check the request for free before you hand anything over. And if the flat itself no longer fits, let Llavai run your Barcelona search so the next place is lined up before you commit to a top-up on this one.