As an expat, one of the first things you have to do after moving to Spain, after finding a place to live (obviously) is to get “empadronado“, which means to register with your local “padrón” or city hall. This is the first step one must take in order to live in Spain legally.
It’s very important for local Spanish authorities to know how many people live in their district – as they get funds from the central government based on number of people registered in their area – so you can go and get empadronado even if you’re an illegal immigrant. All applications are strictly confidential and they won’t use information from the empadronamiento to locate and deport illegal immigrants. This, of course, isn’t my case, since I’m a citizen of the European Union and I can live and work in Spain at will.
In order to get empadronado, you need to fill in a form which they’ll hand out at city hall, your passport / EU ID card and proof that you live where say you live. This usually means a renting contract with your name on it. But if you live in a shared flat, especially if you stay there for a short period of 2 – 3 months, it’s very unlikely that you’ll have a renting contract, because these things are handled in a somewhat clandestine manner. You just pay the rent – cash – and live there. If this is the case, you have 2 ways to get empadronado:
Talk to landlord about empadronamiento
There are some professional “room in shared flat renters” in Barcelona, namely landlords who own one on more apartments and rent them one room at a time to different people. Landlords like this might be willing to help you out with your empadronamiento. But sometimes, your flat-mates are the legal tenants of the flat and they’re sub-renting a room to you without any legal forms. In this case, talking to the landlord is a bad idea that might get all of you kicked out from the flat. So, what then?
Talk to a flat-mate who is already empradonado
If one of your flat-mates is already empadronado at that address, (s)he can come with you at the city hall and vouch for you. Same applies if you live with a friend. The only thing is that the voucher must be empadronado at that address in order to vouch for the vouchee.
I had the most complicated situation of all, since none of my flat-mates were empadronado there. But, one of them got empadronado, since his name was on the renting contract and afterwards he was able to vouch for me. I took us – combined – about 4 hours of waiting in line and 2 trips to the city hall.
Getting empadronado
After you have all your papers in order, you should go to the local ayuntamiento or city hall. Take a book or a newspaper with you, as you usually have to wait in line for something between one and three hours. A PSP will also come in handy 
And a Spanish conversation guide. Be prepared for total lack of English skills. If you have some Spanish speaking friends, ask one to join you. It will save you the frustration. I went with Aurelian as a translator and things went smooth.
Me vs. Spanish bureaucracy 1 – 0