4.3.2.1. All Possible Uses.As “economic demands normally result in an owner’s putting his land to the most advantageous use[,]”286 a property’s highest and best use is ordinarily its existing use on the date of value.287 Many courts describe this precept as a presumption in favor of a property’s existing use;288 others simply regard an existing use as “compelling evidence” of highest and best use when a different proposed use is asserted.289 Either rationale has the same result: to assert a highest and best use other than a property’s existing use, there must be evidence “that this [different] use is ‘reasonably probable’ and that the probability has a real market value.”290 Similarly, in litigation (such as condemnation proceedings), the party claiming a property’s highest and best use is not the existing use bears the burden of proof.291 

Any presumption favoring the existing use does not preclude consideration of other uses in the highest and best use analysis. In fact, any reasonably probable use should be considered to the extent a property’s potential for such use affects its market value.292 As the Fifth Circuit stated: 

owners of property [may seek] to prove, if they can, that the actual use to which they are putting it is not the highest and best use for the property as viewed by a potential purchaser. [But where] there has been no such proof[, t]here is nothing more than speculation that…a purchaser could be interested in buying the land [for another use].293 

Moreover, a potential future use, even if profitable, is not necessarily the measure of the property’s value: “Instead, it is to be considered to the extent the prospect of demand for the use affects market value.”294