Quote from @Sara Pasha:
hi @Chen Zhou, thank you for your posts regarding both your ADUs and willingness to help others in the process. I really liked the way you shared the costs for your 1st ADU project. It would be great if you can share similar one for this ADU if you have it handy. I am also really interested in your thoughts on SB9 lot splits.
I had been starting and stopping my plans for an ADU (as my property had some easement issues). I think I am finally ready to build. But now I am debating whether to build an ADU or do a lot split and built another smaller primary dwelling.
Hi Sara, the all-in cost for this one was $430k. Contractor $300k, finishing materials $60k, solar $10k, public work $10k, soft cost $20k, landscaping and other miscellaneous $30k.
Whether to do SB9 or just ADU really depends on your lot (is it a corner lot? is it big/wide enough for you to divide into two or you have to do a flag lot?). You should also take into account that SB9 would be a lot more costly to do and takes longer. In addition, houses on smaller lot are not valued as much as same houses on a bigger lot, since most of the value of properties in California is in the land.