The ordinance applies to “buildings” not “properties”. So, if no one building exceeds 20,000 square feet the ordinance is not applicable. However, there is one important exception. If two or more buildings share a common meter (with no submeter) such that the energy or water use for a single building cannot be determined, then the square footage of the buildings sharing that meter are summed to arrive at the 20,000 square foot requirement. For example, if a 9000 square foot building and an 11,000 square foot building share a common meter, then the two buildings must be benchmarked as one.