Detailed Answer

Short answer: Not always. In California, probate administration is required only when the decedent owned assets that must pass through probate. Many estates avoid full probate because assets pass outside probate or qualify for simplified non‑probate procedures. Whether you must open probate depends on the types, ownership, and total value of the deceased person’s assets, and whether creditors or title holders require a court appointment to transfer property.

How probate works in California (basic overview)

Probate is the court process to appoint a personal representative (executor or administrator), collect the decedent’s assets, pay debts and taxes, and distribute remaining assets to heirs. The California Courts give a plain‑language overview of probate procedures: California Courts — Probate Self‑Help.

When probate administration is generally required

If the decedent owned real property (land or a house) in their sole name and it does not pass automatically by a transfer‑on‑death deed, joint tenancy, or other non‑probate method, title commonly requires probate to transfer to heirs.
If bank, brokerage, or other financial accounts are solely in the decedent’s name and exceed limits for small‑estate procedures, banks may require probate to release funds.
If creditors must be formally notified and paid, or if the estate has significant debts, probate provides the court‑supervised process for claims.
If multiple potential heirs dispute distribution or need a court to determine intestate succession, probate may be necessary to resolve competing claims.

California’s intestacy rules (how property distributes when there is no will) are set out in the Probate Code; see the statutory framework for intestate succession here: Cal. Probate Code §6400 et seq.

When probate is often not required (common alternatives)

Joint ownership with right of survivorship: Property held jointly automatically passes to the surviving joint owner without probate.
Payable‑on‑death (POD), transfer‑on‑death (TOD), and beneficiary designations: Bank accounts, retirement plans, life insurance, and some securities pass directly to named beneficiaries.
Revocable living trusts: Assets titled in a trust bypass probate; the successor trustee distributes trust property per the trust.
Transfer on Death deeds for real property and small‑estate procedures: California law provides nonprobate methods in some situations; see the Courts and Probate Code for specific programs and forms.
Small estate affidavit / collection without administration: If the value of the decedent’s personal property subject to probate is small enough, an heir or successor can collect certain assets without opening probate using statutory affidavits. See: Cal. Probate Code §13100 et seq. (Collection without administration / small estate rules). Note: the monetary threshold and rules change, so check the current statute or court rules before filing.

Hypothetical examples (to illustrate)

Example A — No probate needed: Maria dies owning a house titled as joint tenants with her adult child and a bank account with a named POD beneficiary. The house automatically belongs to the surviving joint tenant, and the bank pays the POD beneficiary; no probate is needed for those items.

Example B — Small estate procedure: John dies owning a car and $6,000 in a personal bank account, with no real property and no complex debts. If the combined probate assets fall below the small‑estate statutory limit, an heir can often use the small estate affidavit procedure to collect those items without opening a full probate estate. See Prob. Code §13100 et seq.

Example C — Probate likely needed: Susan dies owning a house solely in her name and several accounts without beneficiaries. Because real property generally requires a recorded court order or other nonprobate transfer to clear title, a probate administration is likely necessary to appoint a personal representative and transfer the house to heirs.

Practical steps to determine whether you need probate

Make an asset inventory. Identify all accounts, real estate, titles, insurance beneficiaries, retirement accounts, and trust ownership.
Check titles and beneficiary designations. Determine whether assets are joint, have POD/TOD designations, or are held in a trust.
Compare estate assets to small‑estate procedures. Look at the California Probate Code small‑estate provisions and current monetary thresholds before relying on nonprobate affidavits: Prob. Code §13100 et seq..
Consider creditors and disputes. If the estate has creditors, unresolved claims, or competing heirs, probate may be the safest course.
Get procedural information from the courts. The California Courts self‑help pages explain local filing steps and forms: California Courts — Probate Self‑Help.
Consult an attorney when in doubt. A lawyer can advise whether probate will be required and which simplified procedures (if any) apply given the facts.

When you should get legal help

Consult a probate attorney if you see any of the following:

Real property in the decedent’s sole name.
Larger estates with multiple asset types or significant debts.
Conflicts among family members or potential heirs.
Unclear or missing beneficiary designations, or suspected fraud in titles.
Complex assets such as business interests, foreign property, or tax‑sensitive investments.

Even when probate may not be required, an attorney can help use the right forms and confirm eligibility for small‑estate or other nonprobate options.

Where to read the law

Key statutory starting points (California):

Intestate succession and who inherits without a will — Probate Code §6400 et seq.
Small estate collection without administration — Probate Code §13100 et seq.
General California Courts probate self‑help resources — courts.ca.gov — Probate

Disclaimer: This article explains general California law and is for educational purposes only. It is not legal advice. For advice about a specific situation, consult a licensed California attorney.