What landlords must disclose about mold, and what counts as "untenantable"

By Tyler Vance, California attorney · Updated 2026-09-28 · 3 min read

General information, not legal advice. Every situation is different. If you have a deadline or court papers, don't wait on a guide. Call (562) 644-4186.

Mold questions come up on both sides of a lease. Here is how I explain what "untenantable" means in California, where mold fits, and what the mold disclosure statutes actually say. This is general information, not advice about your situation.

What "untenantable" means

Civil Code section 1941.1 lists conditions that can make a dwelling untenantable. Examples include lacking effective waterproofing and weather protection of the roof and exterior walls, plumbing and gas facilities that aren't maintained in good working order, no hot and cold running water, no heating facilities in good working order, unsafe electrical, and a building that isn't kept clean and free of rodents and vermin. The section also treats a dwelling as untenantable if it is substandard under Health and Safety Code section 17920.3.

Where mold fits

Health and Safety Code section 17920.3 lists substandard conditions. They include dampness of habitable rooms and visible mold growth, as determined by a health officer or code enforcement officer. The statute excludes mold that is minor and found on surfaces that can accumulate moisture as part of their properly functioning and intended use. In practice, that's one reason a code inspection can matter.

When the duty to repair mold arises

Civil Code section 1941.7 says an obligation to repair a mold condition under sections 1941 or 1942 doesn't arise until the landlord has notice of it, or if the tenant is in violation of Civil Code section 1941.2. The same section allows a landlord to enter the unit to repair mold if the landlord follows the entry rules in Civil Code section 1954.

For tenants: tell the landlord in writing. For landlords: respond promptly, give proper notice of entry, and keep records of what was done.

What the mold disclosure statutes say

Two Health and Safety Code sections address mold disclosure:

• Section 26147 requires written disclosure to prospective and current tenants when the landlord knows, or has reasonable cause to believe, that mold is present that affects the unit or building and either exceeds permissible exposure limits set by the Department of Public Health or poses a health threat under the department's guidelines. The landlord isn't required to test. There is an exemption for prospective tenants if the mold was remediated under the department's guidelines.
• Section 26148 requires landlords to give prospective tenants a consumer booklet about mold health risks developed by the department.

Both statutes say they don't take effect until a set time after the department adopts the relevant standards and guidelines (for section 26147) or approves the booklet (for section 26148). Before relying on either statute, check the Department of Public Health's current status on those items.

Practical takeaways

• Tenants: photograph the mold, report it in writing, and consider asking code enforcement to inspect. Don't paint over mold before it's documented.
• Everyone: fix the water source. Mold that keeps coming back usually means the leak or moisture problem hasn't been solved.
• Check local rules. Some cities have additional inspection or disclosure programs.

In habitability matters I represent tenants. If you're a tenant dealing with mold the landlord won't address, start the intake and I'll take a look.

Attorney advertising. This guide is general information about California law as of the date shown, not legal advice, and it may not reflect later changes or local rules. Reading it or contacting me does not create an attorney-client relationship. Results vary and no outcome is guaranteed. Better Call Vance, PC, Tyler Vance, CA Bar No. 318810, 3301 Michelson Drive, Suite 2107, Irvine, CA 92612.