Rent control in the bay area can be extreme as many areas have rent control in excess of the state mandated rent controlIn general experience RE investors are not choosing to add a single ADU in single family zoned areas.  

Even if you rent the house for $2,000 a month, you will still lose because of maintenance, vacancies, and the expensive mistakes common with newer investors.You can borrow up to 70% of the equity.

Tenant moved in the first week of December and there's been an excess of communication from the owners for somewhat minor issues or concerns.- Tenant submitted a work order for low water pressure in 2 bathrooms- Tenant submitted a work order because the garage door doesn't close all the way and left a 2-3 inch gap at the bottom- Owner initially refused to address either work order- Owner demanding the tenants place furniture pads on each piece of furniture- Owner calling multiple times to speak through the work orders, asking when they've been scheduled, calling a couple days later requesting the invoices- Owner calling because they want to access their storage in the basement so they can remove several pieces of furniture being stored- Owner now emailing requesting multiple property inspections throughout the lease cycle- Owner questioning my experience and relative PM knowledge because I'm not following up with her in a timely manner (the following day after the work order)Keep in mind, this is 2 weeks after the tenants had moved in and the tenants are very happy in the home.This is something we see on a regular basis.

Quote from @Matt Meier: If I were to do this, wouldn't the lender lose out on their commission? 

People who fail to keep good tenants and turn over every year, they lose. 

Learning that the slower I move, the more money I lose.

It is a very secure investment, and it is almost impossible to lose money on this deal.

Let's assume that the neighborhood is a C class and the median income of the city is greater than 3X of the market rent.Here are some of the considerations I've come up with so far:- Units are in need of renovation and capex is too high or not available- Unit quality is not the same as market - Seller is worried about losing tenants due to increase- Vacancy rates are high or filling units have been difficult- Rent increase would take multiple increases over multiple lease periods to get to market rate if seller is trying to retain the same tenant- Seller inherited property and just want to liquidate- Seller needs to liquidate quickly (financial burden, sickness, quick exit from land-lording)It seems like I might be missing a warning sign about a deal if they are selling with current rents that are under market; but again, this seems to be most of the properties I've underwritten.And in the same vein, what should I be worried about when purchasing a deal with under market rent with the intention of raising them after purchase. 

If you wait for the problem to occur and then try to educate yourself, you will exacerbate the problem and lose more money.2.

1) Yiu REALLY need to know what CA will  allow you to do, I don’t know, but the state may say too bad landlord, you lose. 2) Assuming your attorney (Or you if you’re able to decode the laws that relate to your situation and are willing to go to court in front of a judge against a “sick” kid.) think you have the right to collect the rent I’d give them two options.