In determining the primary use of a mixed use property, we typically look to the square footage and in the absence of that, we look to the income generated. We have a current scenario where we do not have knowledge of the square footage. In terms of income, the property is only generating income from the residential portion of the buildin and although the commercial space could generate more income, it isn't leased and there's no knowledge as to whether it would be leased in the near future. In terms of best practices, in the absence of square footage information, would you look at the income being generated or would you look at the "potential" income? Thank you in advance.

I think you could use either method, as long as it is well documented and consistent.

An institution may use any reasonable standard to determine the primary use of the property, such as by square footage or by the income generated.

The guide or the reg does not refer to "potential" income.

But would potential income be considered a "reasonable standard"?

Not IMO. If the non-residential portion of the building is not being used then it is not generating any income and there is no reasonable means, lacking a signed lease agreement, that it will generate income in the near future or that it ever will.