Short answer. Yes. Under the Civil Code, an implied warranty or condition as to the quality or fitness for a particular purpose may be annexed by the usage of trade — even when the written contract says nothing about it. What is customary in a particular industry can bind parties the same way an express clause would.
What the law says
An implied warranty or condition as to the quality or fitness for a particular purpose may be annexed by the usage of trade.
Civil Code, Article 1564 — Warranty by Usage of Trade. Read the full provision →
What "usage of trade" means
A usage of trade is a practice or method of dealing that is so regular and well-established in a particular industry or place that parties in that industry can reasonably be expected to know and follow it. Article 1564 says this kind of established custom can attach a warranty or condition to a sale even without any written clause. The logic is that experienced parties in a trade deal against a background of known practices — silence in a contract does not mean a warranty is absent if the trade itself routinely guarantees something.
Quality and fitness are both covered
Article 1564 covers two distinct types of implied warranty: one as to quality (the goods meet a standard common in the trade) and one as to fitness for a particular purpose (the goods will do what the buyer needs them to do, if that need was known). If your industry routinely expects that a certain category of goods will be merchantable, food-safe, or meet a published standard, trade usage can import that expectation into your contract as a warranty even if neither party wrote it down. This is separate from the implied warranties that attach by statute to every sale.
How this affects your contract dispute
If goods you bought or sold are sub-standard and no written warranty clause exists, the question is whether a trade custom existed that created one. Proving trade usage typically requires evidence of how the industry actually operates — invoices, industry standards, trade association guidelines, or testimony from people in the business. The custom must be consistent and well-known, not just an occasional practice. Conversely, if you are a seller being accused of breach, you may argue that no such trade custom applies to your specific market or product category. The outcome depends heavily on the specific facts.
Implied warranties can be excluded, but not always easily
Parties can sometimes exclude or modify implied warranties by express agreement, but courts scrutinize such clauses carefully, especially in consumer transactions. A clause that broadly waives "all warranties" in a commercial contract between sophisticated parties is read differently from the same clause in a sale to an ordinary buyer. If you are relying on an exclusion clause to defeat a trade-usage warranty claim, the language needs to be clear enough to cover the specific warranty being alleged. Vague disclaimer language is often construed against the party who drafted it.