Thanks for all your help everyone, I appreciate the quick and thorough responses. Using the zoning website Seth Teel provided, it is indeed confirmed to be R-5. I also spoke with a zoning associate from the San Antonio development services department who confirmed the property was currently R-5 and intended to be used for a single family residence. However, the property already has four tenant-occupied units, generating the income of a fourplex and has been doing so since 2005. Although the previous owner never had any issues with the city, I'm not sure that is concrete proof there won't be any issues in the future. I would hate to purchase this multifamily property and then one day have the city come tell me it has to be converted back to a single family residence. The zoning associate recommended I start the application for a conditional use permit and stated the process could take up to two and a half months and is contingent upon neighbors within 200 ft being okay with the conditional use permit. I asked her if she knew whether the property was grandfathered in after 2001, but she stated she didn't know and would email me if she could find an answer to that.
I guess my question to you more experienced investors, should I should I buy the home now and assume the issue won't be significant considering the past 13 years of ownership, or should I apply for the conditional use permit and only purchase the home when that is approved? And is there an easy way to find out if a home was grandfathered in with the Unified Development Code in 2001?