You need to make sure that you are buying at a high enough cap rate that you have some fat in the deal to tide you over if vacancy rises.  

A different but related question: what is the cap rate you can expect from a rental property in DC?

108,540 / 2 = 54,270 NOI54,270 / 1,100,000 = 5 capIf you are going to buy at that cap rate you might as well buy a single triple net property at a 6 cap to 7 cap with 2% annual rent increases, no landlord responsibility, and a 15 year lease.This way the tenant pays all the expenses and you just cash the checks.MULTIFAMILY even with a property manager is work.

We’ve covered our bills and put a lot of cap ex into the house, but as a result we haven’t had a ton of cash flow.

What kind of cap rates are you getting in north Chicago?

After working my own numbers on the property as it currently sits its yielding a Cap Rate of 5.2% generating an NOI of around $11,700/yr. 

Cap Rates?

Multifamily (2-4) under 400k with a 5% or more cap rate.

The cap rate is 20%.

Safe rents but lower cap rates.Contrast this with the Midwest or the Northeast where you can pickup rentals for well under $100k in bad/recovering/gentrifying/undiscovered neighborhoods that produce amazing cash flow but many more headaches.