Who has developed duplexes

[Kevin Reid]

I've bought a lot down near Englewood and I hope to build a duplex, maybe a triplex, on it for rental in a few years. It's one of the few duplex lots (RMF10) in the area. 

So who has built a duplex? I'm just trying to get a general feel of the costs? I have power and water nearby, but need a septic system. Any pitfalls to look out for? Any upgrades worth looking at?

Thank you!