The way you construct the building, how high it is elevated, what is in the lower levels, does it have flood mitigations like breakaway panels, etc. all will impact the eventual rate for the Flood Insurance in the National Flood Insurance Program (NFIP).  

Before starting grad school, I spent two years working in a real estate development firm specializing in large-scale commercial and solar projects in NJ and, before that, worked under a general contractor for several years.

Solar powered, well water and septic system.

There might be a panel hidden in one of the apartment closets that gives you access to the main pipe that is capped that drains the shower and the sinks.

Other things they look at is emergency lights, loose railings, chipped paint, cracked walkways that may be a trip hazzard, self closing self locking doors, fire retardant paint on wood panel hallways just to name a few.. 

updated appliances, pulled up linoleum and refinished floors, added electric panels in units, and added instant hot heat/hot water for units Lessons learned?

new HVAC, electric panel, recessed lights, added bathroom, tiled bathrooms, opened up kitchen, new cabinets and appliances, granite counter tops, refinished floors.

It has solar panels and currently producing enough energy where the electricity bill on this 5,500 sqft home is only 25/month.

Also take a look at the grading of the surrounding ground to make sure water flows away from the house, not to the house.Siding can hide many damages, if you see patches or cheap siding recently installed, it is time to start asking , what and why.HVAC, how old, how old is the ducts, take a peak in the the registers, how dirty they are, HVAC handler closet, look for mold in this area, the condensate water drain condition and where it goes.Electrical panel model and manufacturer, google it for recalls.Floor carpet if any, I hate carpet because it hide damages and if it is secure you cant pulled it to look under, look for stains or cold spots, that is an indication of a wet spot. specially near baths Kitchen or egress doors.Kitchens and baths, old or new, try to look behind frig and dishwasher, they hide a lot of  water damages and are very subjectable for mold growth.

The ones I do are an expanded panel for 9 substances of abuse. 95% of my positives are for pot, meth or opiates.