If you are not signed up on the empadronamiento with your local Town Hall, then you should do so, soon. You have until the end of October to do it and to register to vote in the upcoming local elections.
If you don’t sign up, then you can’t register to vote – and, even worse, you might be eligible for additional local taxation, since your home could be considered as a ‘second (home) property” under Spanish Law. Local Government is looking for any and all ways to raise money, and the proposal to tax ‘second homes’ has not gone away. And, by definition, if you are not registered with the local authorities, your house will be designated as such.
So you become easy pickings for Hizzoner. It costs you absolutely nothing to register, so take yourselves down to the Town Hall, potentially save yourselves some money and give yourselves a chance to make your vote count.