Zoned SF Residential but rented as two units

[Greg Betts]

Hello BP community, I need your help. I'm new to all of this, even more so new to zoning and planning rules. Please share advice or expertise. 

I've come across several SFH's zoned SF Residential but the property is being used as a multi-unit dwelling, an example being the basement and upstairs rented out separately. Zoning/planning says the units would be grandfathered if the dwelling was being used as a multi-unit starting in the early 1970's. They won't file a case unless a neighbor complains or requests an investigation so...

Are these situations worth pursuing, should I walk away, does anyone have experience or some guidance?

Thanks!!

[Moore AndKey]

Another consideration that we found on this type of zoning that "grandfathered" means that at no point in time since the property became grandfathered, could it have been vacant.  We understood that a vacancy for any length of time automatically nulls the properties grandfathered status and reverts back to the proper, initial zoning status.  We aren't zoning experts and cant say this is 100 % certain but have understood this to be the case in here in Miami, where MF dwellings or Mother in law additions are commonly not permitted or zoned correctly.  Currently, we generally stay away from these properties when considering deals.  Good luck!  Definitely interested to hear others' perspectives.