4.6.2. Damage.Just compensation is measured by the owner’s loss, not the government’s gain.737 In partial acquisitions when only part of a larger parcel is acquired, the value of the part acquired is not the sole measure of compensation; the “injury or benefit to the part not taken is also to be considered.”738 If the part not acquired, the landowner’s remainder, is “left in such shape or condition as to be in itself of less value than before, the owner is entitled to additional damages on that account.”739 In legal terms, decreases in the market value of the remainder property for which compensation must be paid are compensable damage and must be considered in valuations for federal acquisitions. Compensable diminution in value is also loosely, and misleadingly, referred to as severance damages.740 Compensable damages are not a distinct item to be added to compensation; rather, they are already reflected and automatically included in a before and after method of valuation.741 

But “not all losses suffered by the owner are compensable under the Fifth Amendment.”742 Non-compensable damages cannot be considered in valuations for federal just compensation purposes.743 The distinction between compensable and non-compensable losses is rooted in the market value standard as the measure of just compensation: under the Fifth Amendment, the Supreme Court held, just compensation does not include “indirect or remote injuries” beyond market value “which would ensue the sale of the property to someone other than the sovereign.”744 Such losses are not compensable because they fluctuate with the needs of the owner, not the market; they are “apart from the value of the thing taken.”745 Non-compensable damages have often been called consequential damages, but this term has caused confusion in both valuation and legal analyses.746 

Federal law prohibits consideration of non-compensable damages that may be compensable under many state laws and therefore considered in other contexts.747 Under federal law, some types of damage may be compensable if proved. Some other types of damage—such as lost profits—are never compensable, even if proved, because “not all losses are compensable.”748 And some types of damage may be compensable (if proved) in specific types of acquisitions, but are never compensable in other types of acquisitions.