Renting Property In Mexico - Tax Issues
I am not an accountant or a lawyer and I am not giving you advice.
Here is an opinion and two references. I am pretty sure that ANY income received from a Mexican source is subject to Mexican income tax and should be reported to SAT. Its that simple. (Look for the part about rental income, but the whole article is worth reading). This article (by a known accounting firm) implies non-residents should pay a flat 25% tax, and the 15% IVA tax, and in this case probably a 2% room tax.
Here is another valuable resource for real estate. (look under Taxes on Rental Property) This article also states that you clearly should pay taxes, but has a different set of rules. I think the first set of rules is more current as the laws have changed recently.
A few last points: Another consideration is your FM3 status. Immigration may consider running a pension, or for that matter any set of rental property actively, a lucrative activity and if you have rentista status that might need to be changed. I was told that this decision is up to the individual INM office, but SAT (the Hacienda) may have a different opinion - those two government organizations don't always play by the same rule book as I recently found out. SAT may require an FM3 endorsement that INM does not. The process of changing your FM3 and setting up and RFC with SAT is not difficult at all. See my Kwiki post StartingABusiness
Your rental income also must be reported in the US. There is a tax treaty that keeps you from being double taxed (you get a credit for paying here), but it still has to be reported as does the sale of any property in Mexico. Both Mexico and the US look at worldwide income and expect you to report all sources.
Once again, I am not an accountant or a lawyer and I am not giving advice. I am only sharing information I have found or been told after many hours of research. If anyone else has different information, please share that information with us.