Single Family Property Rented as a Duplex - A "Waldo" Question

[Chris Watkins]

Looking for some advice. I am an investor (and a newbie to the forum). I've spent 5 hours doing my own research on this specific topic already so I hope I'm not wasting anyone's time. I've got a potential opportunity to purchase a "waldo" property. 

It is a 6 bed 3 full bath single family residential home with two separate "units" (3 bd 2 bath up & 3 bd 1 bth down). The zoning is single family residential (R 1-9 in Utah terms). The neighborhood is all single family residential. Through reading the forums it appears the pros to a SFR "conversion" to duplex is cash flow (and it appears to cash flow great). Cons are zoning and difficult resale.

My questions are these: Should I be worried about the potential for me buying this and zoning enforcement coming after me if I rented it out to two households? Is this common for investors to do? If it's been done for years, does that sort of tell me neighbors are okay with it? Am I missing any pros or cons? 

Your help is super appreciated. 

More supporting information about the property: The home was built in 1999. The tenants have done surprisingly well to keep it clean. There is only one gas meter, one water heater, 2 furnaces, 2 separate laundrys and kitchens. The seller has rented it out as a duplex for 6 years. The upstairs is even on section 8 housing for $1050 per month. Downstairs is month to month at $800. The lot actually has a huge 1100 sq ft insulated garage in the back yard which is in addition to the attached two car garage in the front yard. Ideally I could rent that garage out separately as it also is right off the street (perfect for a hobby mechanic shop scenario). 

Here's a top view of the layout. That big rectangle is the shop. 

 The backyard is basically this shop plus a driveway for the basement tenants (basement entrance in the backyard with their own driveway). There is plenty of off street parking in the garages (6 garage spaces in total) plus two driveways.

Thanks for taking the time to help out a newbie to the forums.