ADU (garage) conversion permit in East LA

[James You]

Hi BP community,

Not sure if this is the right forum category to post about this topic since it is something only locals in LA could give advice for.

So my client is buying a home with a garage unit that has been converted into a guest house. We call it ADU here (accessory dwelling unit). The conversion itself is not permitted from the previous seller and my client is looking into getting it permitted with the city. My questions are:

1. Upon closing, is it worth for my client to get the permit through the city? what are the risk and benefit?

2. If my client is able to get the permit approved with certificate of occupancy, would the extra 400 sq ft (garage size) be applied to the total square footage of the house? would it become official on tax records and we can legally market it with the added 400 sq ft when she wants to sell down the road? this will boost huge value to the property.

3. How long does it take to obtain the permit?

This property sits in East Los Angeles and it is very common for properties to have converted guest house in the area without permit. Thanks a lot for your advice in advance.