Converting laundry room into a Studio

[Gilbert A.]

Currently purchasing a 4 unit property in San Bernandino County, SoCal and looking to convert a 144 Sq ft laundry room into a studio to make my property a 5 unit. The laundry room already has gas, water, and a wall heater so it seems like an easy conversion.

Has anyone ever rented a studio this small? Any potential issues you've run into doing so. 

I've also read that this will turn my property into a commercial property because of the 5th unit. Any major cons of property turning into commercial?