Will property tax go up after building an ADU?

[Simon Stahl]

I am about to build an ADU in my garage. Since I want to do it all by code and with permits, the city/county will definitely know about it. What I am wondering now is if my property will be reassessed for tax purposes once the ADU is completed. If so, by how much?

Simon

[Mark Hogan]

Hi, 

I'm an architect who has worked on a lot of these in San Francisco. Your assessment will go up, but not the value of the entire property- I think your original Prop 13 basis will stay the same and they will add the value of the new unit on to it. At least this is the way SF is doing it, and I would expect Oakland is doing something similar. 

If you find out differently let me know.