Dealer classification when flipping??? First time flip

[Jeff Wittig]

Hello everyone. 
So my father and I decided to buy a property together to flip in Spokane Valley, WA. This will be a short term flip and should be completed in 2-3 months. Doing some research shows that with short term we will be taxed at our income tax rate  vs the long term flip capitol gains rate. What I am unclear of is what classify's you as a dealer and what I need to consider about being classified as a dealer. I work a full time W-2 job and my wife is Managing Broker/Property Manager. We also have 4 rental property's that I want to make sure this will not affect for future deals like 1031's etc. Any clarification on this topic would be appreciated. 
Jeff Wittig