Mold and Pests in a Rental: Who Pays, the Owner or the Tenant, in California in 2026?

Published July 15, 2026

Structural leak mold is on the owner. Tenant behavior mold is on the tenant. Heres how California law draws the line.

Under California Civil Code section 1941.1, a landlord must keep a rental free of pest infestation and free of visible mold, but who pays for the fix depends on the cause. If mold or pests trace to a structural problem, a roof leak, a plumbing failure, poor ventilation the building was supposed to have, the owner pays and must fix it. If the mold or pests trace to how the tenant is living in the unit, blocking vents, leaving food out, not reporting a small leak, the tenant is on the hook.

What the statute actually requires

Civil Code section 1941.1 lists the conditions that make a rental "untenantable" under California's implied warranty of habitability. Subdivisions (a)(4) through (a)(6) cover three of the relevant conditions: buildings, grounds, and appurtenances kept clean, sanitary, and free from debris, filth, rubbish, and vermin; adequate garbage and rubbish receptacles; and no infestation of insects, vermin, or rodents. A 2016 amendment, Senate Bill 655, added visible mold growth to the list of substandard conditions under Health and Safety Code section 17920.3, unless the mold is minor and appears on a surface that is expected to accumulate moisture in the course of its normal, intended use, think a shower tile grout line, not a bedroom ceiling.

That matters because Health and Safety Code section 17920.3 is the section that lets local code enforcement or a health officer cite a property as "substandard." Once a unit crosses into substandard territory, the owner is exposed to civil penalties, and in a bad case, criminal misdemeanor liability, not just a tenant complaint.

Who has to fix it, and who pays

California courts and the statute both treat mold and pests as a maintenance obligation the landlord cannot contract away, Civil Code section 1942.1 voids any lease clause purporting to waive the warranty of habitability. But "the landlord must fix it" and "the landlord must pay for it" are not always the same question when the tenant caused the problem.

The practical test that shows up again and again in habitability case law and state guidance is causation:

• Owner responsibility: mold from a roof or window leak, condensation from a failed HVAC or missing bathroom exhaust fan, pest infestation coming in through the building envelope (gaps around plumbing penetrations, cracked foundation, a chronically vacant unit next door), or infestation that predates the tenancy.
• Tenant responsibility: mold from a tenant who never runs the bathroom fan and lets steam sit for hours, pest problems traceable to food storage, un-bagged trash, pet waste, or a tenant who fails to report a small leak for months and lets it become a big one.

A landlord who gets written notice of a leak or an infestation and does not act within a reasonable time can lose the ability to point to tenant conduct at all, because the delay itself becomes the proximate cause. Document the date you got notice and the date you dispatched a vendor. That paper trail is what protects an owner in a habitability dispute or a rent withholding claim under Civil Code section 1942.

The bed bug wrinkle

Bed bugs get their own statute, Civil Code section 1954.603, which requires specific bed bug disclosures in the lease and a defined inspection and treatment process once a tenant reports an infestation. The landlord cannot bill the tenant for bed bug treatment unless the tenant's conduct is proven to have caused the infestation, and even then the landlord still has to arrange the pest control, not just hand the tenant an invoice.

What this means for you

If you own in the South Bay, the fastest way to keep a mold or pest complaint from becoming a habitability claim is speed and paper. Log the tenant's report the day it comes in, get a vendor out within a few days, and keep before and after documentation. If you suspect tenant-caused conditions, a pest control or mold remediation invoice with a cause notation from a licensed vendor is worth far more than your own opinion if the dispute ever reaches small claims or the local rent board.

If you would rather not track notice dates and vendor dispatch windows yourself, that is what we do.

This is general information, not legal or tax advice. Confirm with a licensed professional before you act.

Sources

1. California Civil Code section 1941.1, California Legislative Information
2. California Health and Safety Code section 17920.3, California Legislative Information
3. SB 655 (Mitchell) bill text, California Legislative Information
4. California Civil Code section 1942.1, California Legislative Information
5. California Civil Code section 1954.603, California Legislative Information

Last verified: July 2026.

Topics: playbook, habitability, mold, pest control, maintenance, California landlord tenant law

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Schofield Properties is a family run property management company at 323 Richmond St, El Segundo, CA 90245. We have managed the South Bay since 1972 and personally oversee about 186 doors today. Book a call to talk about your property.