Quote from @Sara Pasha:
Thanks for your thoughts. I dont have a very wide lot, but splitting my lot would give a slightly narrow ~4k sq ft lot. There are a ton of 4k lots in my city and they price well. Only concern is this will be narrow long lot.
I have to research more about the extra costs and time for SB9. The main reason for thinking about lot split is ADUs are not assessed very well yet. In a few years it might become a lot more common and might be assessed to the right value, but unfortunately, we are not there yet.
In your ADU, did you separate the utilities?
Keep me posted on your effort and good luck! In my city (Santa Clara), the application cost of Sb9 is at least $50k+, not including all the additional cost of land survey, public work, adding separate water and gas meters, etc. I think it could be easily $100k-$150k more. And since the reduced lot also reduce the value of the main lot (by $200k-400k), I figured that it was not worth it for me. However, I think for bigger lots and in more expensive zipcodes, Sb9 would make a lot more sense.
I have a separate electric meter (required by the city), but not separate gas/water meter.
