You can now have 3 units on a single family lot in California!!

[Michelle Opal Mills]

So I just learned in California you can now build up to 3 units on a single lot. Thoughts?

http://www.ocregister.com/the-... 

Up to to units can be added no more than 1200 sq ft or 50% of the primary. Cannot be sold as individual units. 

[Chris Mason]

Reminder that Fannie Mae does not care about California law, and about half the value in any real estate is in the fact that you can convert the price into 360 easy monthly payments (aka "you can get a normal mortgage on it"). We know from tv and radio commercials that the way you get top dollar when selling a thing, is to sell it for an "easy monthly payment" rather than sell it for the sales price. A $500 mattress can easily go for $1500 if you sell it as "30 easy payments of $50 each," otherwise top dollar is going to be $500.

Per Fannie Mae:

There may eventually be some catching up on Fannie's part, or there may not be. That's total speculation. 

I would suggest that folks hold off on adding that second ADU (AKA eliminate the possibility of converting your sales price to an "easy monthly payment"), if they plan to sell or refinance the property any time soon. :)