Property Tax: Owner-Occupied vs Rental

[Matthew Kostelic]

First post here, and noob in the game of real estate investing.  I've been reading and learning on here quite a bit, and decided to take action recently on a rental property in Columbia, SC.  I was actually supposed to close this coming Friday (5/31/19) on the home, until I received the closing disclosure yesterday from the bank with an estimated monthly payment that was WAY higher than what we anticipated ($1100 vs $800-850).  The property rents for $1400 with tenants signed to a lease currently.  

The reason for the disparity:  property taxes.  We estimated property tax based on the previous years taxes on Zillow (roughly $1150 on a $155,000 home), and the bank used that in their initial disclosure.  However, when we got the updated disclosure this week, the property taxes were estimated at $4600, and we had no idea why (remember I'm a noob).  After researching it a bit, there is a significant different in the tax assessment ratio & millage rate between owner-occupied and rental properties.  In SC specifically, it equates to ~1.2% for owner-occupied vs 3.4% for rental properties.  

Obviously this threw us for a loop and made the deal unattractive moving forward.  Being new to this realm, is this something I should've known from the beginning?  Should my realtor have made mention of this knowing we were investors looking for investment properties?  Should the bank have run the tax estimate well in advance and let us know before the week of closing?  

Moving forward, are most states similar to this in that they have different assessment ratios and millage rates for owner-occupied vs rental properties?  Are there any loopholes worth exploring to take advantage of an owner-occupied classification for the lower taxes?

Thanks in advance for any replies!