Your RE Investing Advice Appreciated

[Ricio Montes]

Hi everyone! My name is Ricio, and I'm a new member here. Looking for some RE investing advice. For context, I am 34 years old, and I purchased my first RE rental property in SOCAL, in 2011 (it is my only property). The loan amount for that property is currently at $140k with a 4.5 interest rate, and based on online comps, looks like home value is around $600k.

I have about $280k saved for investing (combination of money market accounts, stocks). What I would like to do if the city permits it, is build a detached ADU, and a garage ADU on the same property. The detached ADU would be 2 bed/1 bath, and garage ADU a studio. I'm wondering if this is a good idea considering city permits/building costs etc (this is all new to me). The lot size is approximately 7000 sq ft and the home currently there is about 1000 sq ft, so having two homes of approx. 1000 sq ft and the garage ADU is how I envision things.

As far as financing, I am considering using a HELOC/LOC for the project, and keeping my money as reserves. If it all goes how I am thinking, I would be cash flowing nicely. My main goal as a RE investor is cash flow, and my goal is to be able to reach 10k in monthly cash flows (over time of course).

Could you please advise if this would be a good idea, or if there are better options such as investing out of California. 

Your advice and help are appreciated. Thank you!