Risks of miszoned multifamily

[Max Abend]

I approached a real estate company to learn more about how the owner started and to learn his experience with REI. He mentioned that the best opportunities in southeast Nassau county are buy and hold multifamilies, but that most are not fully legal. For instance, you might be buying a legal triplex that has four or five actual units.

How hard would it be to get such a property rezoned for the extra units in Nassau county (town of Hempstead)? That'd pretty much be the only way I'd consider one of those properties. For someone who did buy, but didn't rezone, what are the risks?