I Cant get the numbers to cash flow on SFHs. HELP!

[Ryan Huddleston]

I am looking at a few SFHs in C areas to BRRRR. Lets say I can pick one up for 20k (I have one in mind actually) put 10-15k in it and the ARV is 70k and it will rent for 700/month maybe 750. I could refinance and take out a 50k loan. Lets say 20 years at 5%

Mortgage $330

Taxes $100

Insurance $100

Vacancy, Cap X, Maint. (5% each) $105

Property Management $70

Total $705

So I'm negative $5 per month. 

Am I missing something? Even on a 30 year loan im only cash flowing around $60/month.