US-CaliforniaDoes the collateral source rule apply in California?
Yes, the collateral source rule applies in California: defendants cannot reduce damages owed to plaintiffs based on benefits the plaintiff received from independent sources like insurance.
What the Law Says
California does not have a statutory collateral source rule — it is a judge-made common law doctrine. Courts have consistently upheld that compensation from independent sources (e.g., health insurance, disability benefits, or gifts) does not reduce the tortfeasor’s liability.
The rule ensures that defendants pay full compensation for the harm they cause, regardless of whether the plaintiff has other financial support. It also prevents wrongdoers from benefiting from the plaintiff’s foresight (e.g., purchasing insurance).
While no statute codifies the rule, California Evidence Code § 351 and § 352 are sometimes invoked in related evidentiary disputes — but neither creates, limits, nor abolishes the collateral source rule.
What Courts Have Said
California courts have repeatedly affirmed the collateral source rule as settled common law, rejecting attempts to limit or abolish it.
Court held that evidence of plaintiff’s Medicare payments was inadmissible to reduce damages, reaffirming the collateral source rule and emphasizing that 'the tortfeasor should not benefit from arrangements wholly independent of his wrongdoing.'
Limited the rule only for *negotiated* medical provider discounts — holding that plaintiffs may recover only the amount actually paid or incurred, not the original billed amount — but explicitly preserved the broader collateral source rule for all other benefits (e.g., insurance payments, wage replacement).
What to Do
Do not deduct insurance payments, disability benefits, or other third-party compensation when calculating your claimed damages.
Object promptly if the opposing party tries to introduce evidence of collateral benefits to reduce damages — it’s generally inadmissible.
Cite Howell (2012) and Hanh v. Dinh (2014) to support admissibility objections or damage calculations.
Consult an attorney if your case involves medical billing disputes — the Howell exception applies narrowly to write-offs, not payments.
Sources
Not legal advice. This article is general information based on publicly available sources, written for educational purposes. Laws change and individual situations vary. Consult a licensed attorney in your jurisdiction before acting on anything you read here. Last reviewed: 2026-06-08.