Contesting a Will in California: Grounds and Process

Reviewed by Gregory J. Borawski, Partner, past Chair of the SDCBA Estate Planning, Trust and Probate Law Section.

A will contest in California is a formal court challenge asking a probate judge to declare a will, or part of it, invalid. Only certain people may bring one, only specific legal grounds will support one, and strict deadlines apply. At Brierton, Jones & Jones, LLP, a Women-Owned San Diego firm devoted exclusively to trust and estate matters, we have guided San Diego County families through these disputes for more than 30 years.

What Counts as a Will Contest in California

A California will contest challenges the validity of the document itself, not the fairness of how assets were divided. A probate judge cannot rewrite a will because the split feels unfair. The court can set a will aside only when the filer proves a recognized legal defect in how it was made or signed.

Under California Probate Code section 48, only an "interested person" may file. That group generally includes beneficiaries named in the will, beneficiaries named in an earlier will, heirs who would inherit under California's intestate succession rules if no valid will existed , and creditors of the estate.

Simplified Definition: Interested Person: Someone whose own inheritance or financial claim would change if the will were declared invalid. If setting the will aside would not affect what you receive, you generally cannot contest it.

A contest can also target one provision, leaving the rest of the will intact.

The Legal Grounds for Contesting a Will in California

Every contest must rest on a recognized legal ground. Probate Code section 8252 allocates the burden of proof across those grounds: lack of testamentary intent or capacity, undue influence, fraud, duress, mistake, and revocation. Probate Code section 21310(b) uses a closely related list to define a direct contest for no-contest clause purposes. Several grounds often appear together in one case.

Lack of Testamentary Capacity

Lack of capacity means the person signing did not have the mental ability the law requires. Probate Code section 6100.5 sets the test. Capacity is missing if, at the time of signing, the person could not do any of the following:

• Understand the nature of making a will.
• Understand and recall the nature and situation of their property.
• Remember and understand their relationships to living descendants, a spouse, and parents, or to anyone whose interests the will affects.

Capacity also fails when a mental health disorder produces delusions that cause someone to leave property in a way they otherwise would not have. Capacity is measured at the moment of signing, so a dementia diagnosis does not by itself invalidate a will.

Undue Influence

Undue influence is excessive pressure that overcomes the free will of the person making the will. Welfare and Institutions Code section 15610.70, imported into the Probate Code by section 86, directs courts to weigh four factors: the vulnerability of the person influenced, the apparent authority of the influencer, the tactics used, and the equity of the result. An unequal result on its own is not enough. There must be evidence of the persuasion that produced it.

Under Probate Code section 21380, a gift to the drafter of the document, to a transcriber in a fiduciary relationship with the signer, or to the care custodian of a dependent adult is presumed to be the product of fraud or undue influence. The care custodian presumption reaches only wills signed during the period of care or within 90 days on either side of it.

Most of those presumptions can be rebutted by clear and convincing evidence. A gift to the drafter cannot. Section 21380(c) makes that presumption conclusive, and a beneficiary who fails to rebut bears the costs of the proceeding, including reasonable attorney fees. These claims often overlap with financial elder abuse. For the evidence courts weigh, read our guide to undue influence in California.

Fraud, Duress, and Menace

Fraud occurs when someone is deceived into signing a will or into including terms they did not intend. A caregiver who falsely tells an aging parent that a child has abandoned them is a common example. Duress and menace involve threats or coercion that force a signature.

Improper Execution

Improper execution means the will was not signed and witnessed the way California law requires. Probate Code section 6110 calls for a written document, signed by the testator, and witnessed by at least two people present at the same time who understood it was a will. Section 6110(c)(2) offers a safety valve: a flawed will can still stand if the proponent proves by clear and convincing evidence that the person intended it as their will. These defects surface most often in do-it-yourself estate planning never reviewed with counsel.

Forgery and Revocation

Forgery claims the signature is not genuine. Revocation claims the person cancelled the will before death, often by signing a later will or destroying the original.

Deadlines: The 120-Day Rule and Pre-Probate Objections

An interested person generally has 120 days from the date a will is admitted to probate to petition the court to revoke that order. Probate Code section 8270 sets this deadline, and missing it usually ends the challenge for good, no matter how strong the underlying facts are.

Section 8270 also excludes two groups from that window: anyone already a party to a will contest, and anyone who had actual notice of a contest in time to join it and chose not to. If a sibling contested the will and you stayed out, you generally cannot raise the same challenge later.

There are two timing points, not one.

• Before the will is admitted. Probate Code sections 8004 and 8250 allow an interested person to file a written objection at or before the hearing on the petition for probate. Acting here is often less costly.
• After the will is admitted. Section 8270 opens the 120-day window to petition for revocation of probate.

One narrow exception applies. A person who was a minor, or incompetent with no guardian or conservator when the will was admitted, may petition any time before the order for final distribution.

How to Contest a Will in San Diego Probate Court

To contest a will in California, an interested person files a written objection in the probate court where the estate is pending, then serves a summons on the heirs and beneficiaries. Probate Code section 8250 requires the summons to direct those served to respond in writing within 30 days.

The matter then proceeds like other civil probate litigation. Discovery typically includes document requests, subpoenas for medical and financial records, and depositions of the drafting attorney, witnesses, and caregivers. Many contests settle or resolve at trust and estate mediation, and those that do not are tried before a probate judge.

Burdens of proof are split. Probate Code section 8252 places the burden of proving due execution on the people offering the will, while the contestant carries the burden on the grounds of the contest. Our trust and estate litigation team handles these matters in San Diego County courts.

Proving Your Case: Evidence and Burden of Proof

Winning a will contest in California requires documented evidence, not family suspicion. Judges do not overturn a signed will because one sibling received more. The evidence that carries the most weight includes:

• Medical records from the months surrounding the signing, including cognitive assessments and physician notes.
• The drafting attorney's file, including intake notes, correspondence, and capacity observations recorded at the signing.
• Witness testimony from the attesting witnesses, caregivers, and family who saw the person's condition.
• Financial records showing account, property, or beneficiary changes in the same period.
• Prior estate planning documents showing a long-standing plan the new will reversed.
• Expert opinion on capacity or signature authenticity.

Outcomes turn on the specific facts, so speak with a licensed California attorney before deciding whether to file.

No-Contest Clauses and the Probable Cause Exception

A no-contest clause threatens to disinherit a beneficiary who challenges the will, but California enforces these clauses only in limited circumstances. Probate Code section 21311 permits enforcement against a direct contest only when that contest was brought without probable cause.

Simplified Definition: Probable Cause: Under Probate Code section 21311(b), probable cause exists if the facts known to you when you file would cause a reasonable person to believe there is a reasonable likelihood the court will grant the relief you seek. The court measures that belief after a fair chance to investigate or conduct discovery.

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You can lose a will contest and still keep your inheritance, as long as you had probable cause when you filed. What triggers the penalty is filing with no reasonable basis. Section 21311 also reaches property-ownership challenges and creditors' claims when the clause expressly says so.

The deadline and the clause intersect. California courts have held that a contestant who files after the limitations period has run lacks probable cause, because no reasonable person could expect a time-barred petition to succeed. A late filing can trigger the clause on top of losing the case.

Because that analysis turns on what you knew on the filing date, reviewing the evidence before you file is the step that most affects whether the clause can reach you. For how these clauses operate, see our guide to no-contest clauses across wills and trusts.

Frequently Asked Questions About California Will Contests

Key Takeaways

The grounds for contesting a will in California are lack of testamentary intent or capacity, undue influence, fraud, duress or menace, improper execution, forgery, and revocation, governed by Probate Code sections 6100.5, 6110, and 8252.

An interested person generally has 120 days from admission to probate to petition for revocation under Probate Code section 8270. An earlier objection under sections 8004 and 8250 is usually the less costly path.

Under Probate Code section 21311, a California no-contest clause reaches a direct contest only when it was filed without probable cause. Losing a contest does not by itself forfeit the inheritance.