San Francisco Fire Department Administrative Bulletin 2.04
- Apr 15
- 2 min read
On a recent project call, our Founder ran into a surprise new Fire Department requirement that will have a significant impact on the cost of housing, especially for small ADU and legalization projects.
When the building code changed last year, the Fire Department tightened the fire sprinkler requirements for ADU and legalization projects. You now have to use the highest level of fire sprinkler system - the one used for high-rises and huge structures - on these smaller areas. As of January 1, 2026, these new requirements apply to all new projects, including those already in the pipeline and submitted prior to the official code change. If you’ve got a project in the pipeline, congratulations - you get to give your client a very unwelcome surprise price increase.
Since 2015, ADU and legalization projects have only required a partial fire sprinkler system, generally at the ground floor or at the new unit and the path of travel to it (the Residential (NFPA 13R) system). This was an exception made to the Building Code, which otherwise required the entire building to be sprinklered.
Buried on an obscure part of the Fire Department website, in a new Administrative Bulletin (AB 2.04), is the culprit. We went through this document with a fine-tooth comb to find this: “New partially sprinklered NFPA 13D and NFPA 13R systems are prohibited. Only NFPA 13 systems are permitted to be partially sprinklered.”
Oof. There it is: when you’re only sprinklering part of a building, you must use the highest level of fire sprinkler system. These systems come with all kinds of hidden costs - you need to trench a dedicated water line into the street, provide a separate water meter, install a backflow preventer, and connect to the city main. Suddenly, construction of a single ADU unit or legalization comes with an increased price tag of over $35K just for the new fire sprinkler system. Brutal.
We’ve reached out to the head of Fire, the head of DBI, and the head of Planning about this issue. We’ve also contacted Supervisor Melgar’s office, but we haven’t made any progress on this issue. For now, be sure to budget for extra costs on those small projects!
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