In Richins Drilling, Inc. v. Golf Services Group, Inc., the Utah Court of Appeals clarified what type of testimony fell within the parol evidence rule. On appeal was the judgment of the trial court in favor of the appellee on the appellant’s breach of contract, unjust enrichment and mechanics’ lien claims. The contract for well-drilling work between the parties stated that “[the appellee] shall not unreasonably withhold approval of all such work, when performed by [the appellant] in accordance with the generally accepted practices and methods customary in the industry.” In determining what were “generally accepted practices and methods customary in the industry,” the trial court relied on expert witness testimony. Based on this expert testimony, the trial court found that the appellant had breached the contract by going over the maximum contract price, using drilling methods not conforming to industry standards and finishing the project after the time for completion. None of these contract terms were specifically included in the contract but were instead incorporated into the contract through the term requiring “generally accepted practices and methods customary in the industry.”

On appeal, the appellant argued that the trial court had violated the parol evidence rule by impermissibly adding these contract terms to the contract. However, the Court of Appeals found for the appellee on this issue and affirmed the judgment of the trial court. The Court of Appeals held that the appellant had mischaracterized the applicability of the parol evidence rule, which operates to exclude evidence of prior or contemporaneous conversations of the parties to a contract which would alter the terms of that contract. Rather, the Court of Appeals held that the appellant had “confused the applicability of the parol evidence rule with the trial court’s interpretation of the contract.” The Court of Appeals held that the expert testimony evidence was not evidence of any prior or contemporaneous agreement between the parties, but was evidence utilized by the trial court to interpret the express terms of the contract. Therefore, the Court of Appeals deferred to the trial court’s interpretation of the contract and affirmed its decision. Richins Drilling, Inc. v. Golf Services Group, Inc., 189 P.3d 1280 (Ut. 2008).