So you are told its impossible to cash flow in LA. Actually you can, it just requires slightly more cash down. You can also try lowering expenses, although that might barely make a difference.

If data from Zillow is correct, current median listing price for a home in LA is about $749,000. You can almost forget about a nothing down purchase... with a 20% down payment, 4.7% 30-year conventional mortgage rate and financing the principal of: $599,200, your monthly mortgage payment would equal: $3108. 

But median LA rent for a home appears to be about $3500. We already see some problems here. To break even, you would have to keep total expenses at 11.21% or $392 per month -- thats a long ways from 50% suggested by the 50% rule. Using estimated expenses of 45%, the result is a monthly negative cash flow of $1,182.68. 

So owner would have to incur an additional out of pocket expense of $14,192.13 per year, just to maintain property and hoping property appreciates in value in excess of this amount just to soften the hit.

In order to break even, and we aren't even talking positive cash flow yet, you would need a down payment of about 50.45% of the property value to significantly reduce loan principal. 

Example: holding all else constant,  50.45% of the $749,000 in cash for the down would reduce loan principal to about $371,165 which then enables property owner to break even. 

Is a 50% down payment weird or normal in your market? 

So if you thinking about scooping up a rental in LA, the real question is, how much down you planning to play with?