Help! Are My Assumptions Reasonable?

[Sean Autry]

Hi All-  Newbie investor here, searching for my first rental property.  This has been a goal of mine for many years and I'm finally in a place to pull the trigger.

I live in So. Cal and (though sparse) I'm able to find a number of deals right on the MLS that cash flow reasonably well based on my model- to the tune of 9% - 17% cash on cash (levered up from 5% - 8% cap). I've heard over and over again that getting those kinds of returns in CA (absent appreciation) is pretty uncommon.

SO... What am I missing?  Are those returns realistic? I feel like I must be missing something.  I'm using the below to arrive at my monthly net cash flow number:

• +Rental Income
• (-) Vacancy Assumption = 8% of rent
• (-) Mgmt Fees = 10% of rent
• (-) Mortgage Interest Expense = 4% rate
• (-) HOAs = Actual
• (-) Insurance = 6.8% of annual rent
• (-) Property Tax = Actual per MLS
• (-) Repair/Maint = 10% of rent
• (-) Gardner = $50/mo
• = Net Rental Income
• (-) Mortgage Principal Paydown
• =Net Monthly Cash Flow

Any input is very much appreciated.  Thanks!

Some Geography Context:  I'm looking in San Bernadino, Apple Valley, San Jacinto, Hemet, Adelanto, Riverside, LA, and other low-price areas.  I am also interested in out of state investing, but I'll leave those questions/comments for another post.