Owners who rent out a second home during the summer must declare the income on their tax return or risk facing costly surcharges and penalties from Spain's Tax Agency, according to the agency's own guidance.
A second home is often used by owners for a getaway, especially when it sits on the coast. But when the property is also rented out during the summer to earn extra income, that changes its tax treatment. Even if the rental lasts only a few weeks or months, the income must be reported on the personal income tax return, known as the IRPF.
Failing to declare that income can end up costing far more than the amount originally left unpaid, once surcharges, interest or penalties are applied.
Harder to hide from the Tax Agency
The Tax Agency has tools to cross-check IRPF filings against Cadastre records. Digital platforms are also required, under the European Union's DAC7 directive, to report certain user activity, including information related to rentals, making the omission increasingly difficult to conceal.
In its own manual for the 2025 tax return, the Tax Agency notes that a home used exclusively during the summer months still generates an imputed real estate income that must be included in the declaration. That obligation does not disappear simply because the property was rented out for only part of the year.
Taxpayers who realize the mistake after the filing period has ended can still correct it voluntarily and avoid harsher consequences, according to sources at TaxDown cited by Demócrata.
Fixing the error before the Tax Agency catches it
The first step is determining whether leaving out the rental income changes the outcome of the return. If the correction means the taxpayer owes more, or that a refund already received should have been smaller, a supplementary declaration must be filed.
Acting voluntarily before the Tax Agency detects the irregularity can make a significant difference to the final cost. In these cases, the surcharge set out in Article 27 of the General Tax Law applies: 1%, plus another 1% for each full month of delay past the end of the voluntary filing period.
During the first twelve months of delay, no late-payment interest or penalties apply. Beyond that period, the surcharge rises to 15%.
Penalties can reach 150%
The situation becomes far worse if the Tax Agency itself detects the omission first and sends the taxpayer a formal notice. In that case, the agency can open a penalty proceeding.
For amounts left unpaid, penalties generally start at 50% of the unpaid sum, and can climb as high as 150% when aggravating circumstances apply.
The tax treatment of a second home also is not identical throughout the year. During the period when the property is rented out, the owner must declare the rental income along with any deductible expenses linked to the arrangement.
For the days when the property remains available to the owner rather than rented, the proportional imputed real estate income rule applies instead. As a result, even if the home is only rented for part of the summer, its different uses during the year must be reflected correctly on the tax return.
