You're correct about the stringent rent control, so I don't understand the HUGE hike. The guy MIGHT be running a business from where he is as well. We aren't hearing the entire story, I think.
I haven’t seen anyone here discuss other factors like “what is the property tax situation on the property for the owner?” “What are the insurance costs?” “What are the licenses, fee and permit costs, if any?”
For $1800/month for a single tenant, SF property taxes could be even higher than that. The city beast MUST be fed you know.