Philadelphia CMX-3 question

[Owen Lee]

Hello, I'm looking to purchase a CMX-3 property currently as a single family. The current owner never bothered to get a use permit/variance for single family use. It's been rented out for years without an issue.

But I believe there was a recent change to Philly zone rules for CMX-3 in that, single family use is no longer permitted. 

Is the property a risk to purchase now, or there's some way to still get the use permit for Single Family?

Any feedback on the matter is appreciated!