How to Respond to an Unlawful Detainer Lawsuit in California

California Tenant Defense System | Justice Foundation

When a landlord files an unlawful detainer (UD) lawsuit — California’s eviction proceeding — the clock starts immediately. You have five days from service of the summons to file a written response with the court. Miss that deadline and a default judgment will be entered against you, allowing the landlord to obtain a writ of possession and have the sheriff lock you out. Five days is very little time. This post tells you exactly what to do.

Identifying What You Were Served

The UD package includes a Summons (UD-105), a Complaint (UD-100), and the notice that preceded the lawsuit. Read all of it immediately. The summons identifies the court, the case number, and the response deadline. The complaint states the landlord’s grounds for eviction. The preceding notice — the 3-Day, 30-Day, or 60-Day notice — is a critical document because defects in that notice are complete defenses to the lawsuit.

Filing Your Response: The UD-105

Your written response is filed on Judicial Council Form UD-105 (Answer — Unlawful Detainer). This form allows you to deny the landlord’s allegations and assert affirmative defenses. Critical defenses to consider: defective notice (wrong amount, improper service, incorrect form), failure of the landlord to maintain the unit in habitable condition, retaliation for protected tenant activity, discrimination, failure to follow proper procedure under AB 1482 or local rent control, and waiver (if the landlord accepted rent after the violation they’re now using as grounds for eviction). You may assert multiple defenses on the Answer form.

Filing and Service

File your Answer at the courthouse listed on the Summons before the five-day deadline — courts close at 4pm or 5pm, so plan accordingly. Pay the filing fee (fee waivers are available for income-qualified tenants). Serve a copy on the landlord or their attorney by mail on the same day you file. Keep your file-stamped copy permanently.

After Filing

Once your Answer is filed, the court will set a trial date — typically within 20 days. Use that time to gather evidence: habitability documentation, rent payment records, the landlord’s history of communications, any evidence of retaliation or discrimination. The Justice Foundation Tenant Defense Kit includes a completed UD-105 template with all available defenses pre-populated and instructions for selecting the ones that apply to your situation.