California sets no statutory maximum on how long a non-disclosure agreement can last. For ordinary confidential business information, the duration has to be “reasonable,” which in practice usually means somewhere between two and five years. For genuine trade secrets, an NDA can last indefinitely, for as long as the information stays secret. Anything beyond those limits risks being thrown out entirely.
The Reasonable Duration Standard for Confidential Information
When an NDA covers ordinary confidential information rather than trade secrets, California courts expect the duration to be reasonable in light of the circumstances. There is no bright-line statute setting a number of years. A court instead looks at how long the protected information retains its competitive value, what the industry norm is for similar agreements, and whether the time frame imposes an unfair burden on the person bound by it.
Information with a short shelf life warrants a shorter NDA. Quarterly sales projections, for example, lose their competitive edge within a year or two. A multi-year strategic business plan could justify a longer window. In practice, most California NDAs covering non-trade-secret information run between two and five years, measured either from the date of disclosure or from the end of the business relationship, whichever the parties choose as the trigger.
The key question a court asks is whether the duration matches the information’s useful life. A ten-year NDA covering routine financial data that becomes stale after a single fiscal year would be difficult to defend. A five-year restriction on a proprietary algorithm still in active commercial use is far easier to justify.
Trade Secrets Can Be Protected Indefinitely
The biggest exception to the reasonable-duration standard is trade secrets. Under the California Uniform Trade Secrets Act, information qualifies as a trade secret when it gains economic value from not being publicly known and the owner takes reasonable steps to keep it secret.1California Legislative Information. California Code CIV 3426.1 – Definitions Formulas, manufacturing processes, proprietary software code, and carefully maintained customer databases are common examples.
An NDA protecting a genuine trade secret can last as long as the information qualifies. If a secret formula remains unknown to competitors for decades, the NDA stays enforceable for decades. Protection ends only when the information enters the public domain, whether through independent discovery, reverse engineering, or the owner’s own failure to keep it confidential.
To maintain trade-secret status, the owner has to take active steps. Marking documents as confidential, restricting access to employees who genuinely need the information, requiring NDAs before disclosure, and maintaining security protocols all matter. Stamping “TRADE SECRET” on a document without any real access controls will not meet the statutory standard.1California Legislative Information. California Code CIV 3426.1 – Definitions
Separate the Two Categories in the Agreement
Drafting matters enormously here. A well-written NDA distinguishes trade-secret information from other confidential material and gives each category its own duration. Trade secrets get protection “for so long as the information remains a trade secret,” while ordinary business data gets a fixed term of years. An NDA that lumps everything together and applies an indefinite duration to all of it invites a court challenge, because not everything shared in a business relationship rises to trade-secret status.
When Duration Turns an NDA Into an Illegal Non-Compete
California has one of the strongest bans on non-compete agreements in the country. Under Business and Professions Code section 16600, any contract that restrains someone from engaging in a lawful profession, trade, or business is void.2Justia Law. California Code BPC 16600-16607 Since 2024, employers cannot even attempt to enforce such a provision, regardless of where the contract was signed, and a violation can lead to a civil action for damages and attorney’s fees.3California Legislative Information. California Code BPC 16600.5
This matters for duration. If an NDA defines “confidential information” so broadly that it covers general industry knowledge, skills you developed on the job, or relationships with people in your field, it effectively prevents you from working for a competitor. Courts will treat that kind of NDA the same way they treat a non-compete: void and unenforceable. A very long term stacked on top of very broad categories of information looks more like a non-compete than a genuine confidentiality measure, and courts read the two features together.
Limits That Apply No Matter How Long the NDA Lasts
Duration is not the only limit on what an NDA can do. Even a reasonably timed NDA cannot reach into certain subject areas.
Workplace Harassment, Discrimination, and Retaliation
California law prohibits employers from using confidentiality provisions to silence employees about unlawful workplace conduct. Under Government Code section 12964.5, an employer cannot require a worker to sign an NDA that prevents the disclosure of information about harassment, discrimination, or retaliation, and any nondisparagement or confidentiality clause has to include language, in substantial form, telling the employee that nothing in the agreement prevents them from discussing unlawful acts in the workplace.4California Legislative Information. California Code GOV 12964.5 This applies to both employment and separation agreements.
Settlement agreements face similar restrictions under Code of Civil Procedure section 1001. A provision that prevents disclosure of factual information related to sexual assault, sexual harassment, workplace harassment or discrimination based on sex, or retaliation for reporting such conduct is void as a matter of law.5California Legislative Information. California Code CCP 1001 The settlement amount itself can stay confidential, and the claimant’s identity can be shielded if the claimant requests it.
Communications With Federal Regulators
No NDA can block communications with federal regulators. Under SEC Rule 21F-17(a), it is illegal to take action to prevent someone from communicating directly with SEC staff about a possible securities law violation, including enforcing or threatening to enforce a confidentiality agreement.6SEC.gov. Whistleblower Protections Similar protections apply under other federal whistleblower statutes covering agencies like OSHA and the DOJ. If your NDA purports to prevent you from reporting potential violations to a federal agency, that provision is unenforceable regardless of what the rest of the agreement says.
What Happens If a California Court Finds the Duration Unreasonable
If a California court decides an NDA’s duration or scope is unreasonable, it will not rewrite the agreement to save it. This is a critical difference from many other states, where courts use a “blue pencil” approach to narrow overbroad restrictions to an enforceable scope. California’s strong public policy against restraints on competition, rooted in Business and Professions Code section 16600, means courts are far more likely to void an unreasonable provision outright.2Justia Law. California Code BPC 16600-16607
The consequences fall entirely on the drafter. If a court voids the confidentiality provision, the person who signed is released from the obligation. In extreme cases where the terms are fundamentally oppressive or one-sided, a court may void the entire contract rather than just the offending clause. Overreaching on duration doesn’t risk partial enforcement; it risks losing all protection. An NDA that clearly separates trade secrets from other confidential information, assigns each category an appropriate duration, and avoids language broad enough to restrict the signer’s ability to work in their field will hold up. One that tries to lock down everything indefinitely will likely protect nothing at all.