Wholesaling... and Zoning Question

[Jeff G.]

I've gotten a response from a Realtor regarding a yellow letter I sent his client. We've been playing telephone tag but finally got a chance to really discuss the property today. It's a small house (950 sq ft) on a respectable lot (2+ acres) in need of a full-gut rehab.

However, I just realized the area is zoned I-1 (light industrial) and is no longer residential.

When I questioned the Realtor about it he confirmed what I already knew. But, indicated that he was under the impression from the city that the property itself was grandfathered as residential as long as it was still standing.

Before I get this property under contract I want to confirm that his understanding is accurate. As the old proverb goes, doveryai, no proveryai trust, but verify. 

Is it enough to email the city zoning office and ask? Or, do I need a specific document from the zoning body as hard evidence property itself is grandfathered as residential inside the I-1 zone?

Thanks!