San Francisco- Multiunit building- legalizing 3rd unit

[Matthew Wright]

Hi BP members, I have a building in San Francisco that is classified as a 2 unit building, in reality it is x3 apartments, the ground floor work was done prior to acquisition and not permitted. I do not want to turn into a x3 unit building due to creation of HOA etc. Medium term I would likely look to combine the middle and lower units. For the ground floor (non-permitted) we need to do some bathroom improvements which are not presently to code. I would do these to current code standards, and other smaller alterations all to code, without gaining permits. Then when it comes time to legalize, looking to get everything approved at once, with the data point that it was built to code in the past. Does anyone have experience legalizing prior no-permitted additions in SF and can advise if this is a good or terrible idea?

Thanks!!