Mold in an LA Rental: What California Law Asks of the Owner

For Owners · Repairs & Habitability · October 2026 · 10 min read

A tenant sends a photo of black spotting along the ceiling above a shower and asks what you are going to do about it. Is that a habitability problem, a cleaning problem, or a ventilation habit? The answer matters, because California ties the repair duty, the tenant’s remedies and the protection against retaliation to that one question.

This guide covers what the state’s housing law says about mold, when an owner’s duty to repair it begins, what the state’s mold disclosure statutes actually require today, who inspects in Los Angeles County, and a way to handle a mold report that holds up later. Every rule here comes from the statute or the agency’s own published guidance, linked at the end. For the wider repair framework, see our guide to repair requests and habitability.

When mold makes a unit substandard

Section 17920.3 of the Health and Safety Code lists the conditions that make a building substandard when they exist “to an extent that endangers the life, limb, health, property, safety, or welfare” of the occupants, neighbors or the public. Two items on the inadequate-sanitation list touch mold:

• Paragraph (11): dampness of habitable rooms. It does not require any mold at all.
• Paragraph (13): visible mold growth, “as determined by a health officer or a code enforcement officer,” excluding “mold that is minor and found on surfaces that can accumulate moisture as part of their properly functioning and intended use.”

The California Department of Public Health notes that this mold language has been in the housing code since January 1, 2016. Three parts of the wording do real work:

• Visible. The paragraph is about growth someone can see. A musty smell or a lab report alone does not meet it, though dampness under paragraph (11) can.
• Determined by an official. It is a health officer or code enforcement officer who decides whether the growth qualifies, not the tenant, the owner or a private inspector.
• The minor-mold exclusion. The statute does not list examples. A shower enclosure is the kind of surface the words describe, because getting wet is its intended use. Growth spreading across the ceiling or into drywall around that shower is a different question.

When the repair duty starts

Civil Code section 1941.7 is short. It says no obligation arises under sections 1941 or 1942 to repair mold covered by paragraph (13) “until the lessor has notice of the dilapidation or if the tenant is in violation of Section 1941.2.” Two consequences follow.

First, the clock starts with notice. A text, an email, a call to your manager or a note in the maintenance portal can all put you on notice, so the date the report came in is the date to record. Under section 1942, a tenant who has given notice of a condition that makes the unit untenantable and waited a reasonable time may repair and deduct up to one month’s rent, no more than twice in 12 months, and 30 days after notice is presumed reasonable.

Second, the same section confirms you may enter to repair mold, as long as you follow the entry rules in Civil Code section 1954: written notice, a lawful purpose, normal business hours outside an emergency. Our guide to landlord entry notice walks through the notice periods.

What the tenant owes in return

Section 1941.2 lists the tenant’s side of habitability: keep the part of the premises they occupy clean and sanitary as conditions allow, dispose of garbage and trash in a clean and sanitary way, use the plumbing, gas and electrical fixtures properly and keep them as clean as conditions allow, not damage the premises or let anyone else do it, and use each room for the purpose it was designed for.

Section 1941.7 carves mold out of the repair duty when the tenant is in violation of section 1941.2. That is a fact question. A tenant who never runs a working bathroom fan may be part of the cause. A tenant living with a roof leak is not. Before treating a mold repair as tenant-caused, get the cause in writing from the person who opened up the wall or traced the moisture, with photos taken before the repair starts.

No exposure limit and no testing duty

The Toxic Mold Protection Act of 2001 (Health and Safety Code sections 26100 and following) told the state health department to adopt permissible exposure limits for indoor mold “if the department finds that adopting permissible exposure limits to mold in indoor environments is feasible.” The department’s current answer, on its mold FAQ page: “Science-based exposure limits for indoor molds cannot be established at this time, and none exist in California.”

That has practical effects for owners:

• No testing duty. Section 26147(b) says a residential landlord is not required to conduct air or surface tests. The state department says it does not recommend testing for mold, and the Los Angeles County Department of Public Health says sampling and testing “is not necessary to know the health risk.”
• Species is not the issue. The state department says there is no evidence that the particular kind of mold in a building matters. A tenant asking whether it is “black mold” is asking the wrong question. The right one is where the water is coming from.
• Private reports carry limited weight with the County. The County’s Rental Housing Habitability Program says it does not accept third-party inspection reports, such as mold inspection reports, as evidence of violations or of compliance. Its inspectors observe and verify for themselves.

The mold disclosure laws on the books

Two sections of the same act speak directly to residential landlords:

• Section 26147 requires written disclosure to prospective and current tenants of affected units when the landlord knows, or has reasonable cause to believe, that mold is present that affects the unit or building and either exceeds the permissible exposure limits or poses a health threat under the department’s guidelines. Prospective tenants get it before signing; current tenants in affected units as soon as reasonably practical. Mold remediated under the department’s guidelines removes the duty to prospective tenants.
• Section 26148 requires giving prospective tenants a consumer booklet on the health risks of mold, developed and approved by the department, before the lease is signed.

Both are conditional. Section 26147(e) says it does not apply until the first January 1 or July 1 at least six months after the department adopts the exposure limits and assessment standards and develops remediation guidelines. Section 26148(c) ties itself to the department’s approval of the booklet. Since the department says no exposure limits exist, the trigger in 26147 has not been met on the department’s own account. We could not confirm from the department’s published material whether a booklet has been formally approved under 26148, so we are not telling you that section is in or out of force.

Two practical points. Handing a new tenant the state department’s plain-language mold information at lease signing costs nothing, though we cannot say it would satisfy 26148 if that section turns out to be in force. And if you know about mold in a unit you are about to rent, fix it first and keep the paperwork. Whether a disclosure duty exists outside these sections is a question for a real estate attorney, not this article.

If you own mixed-use or commercial space, the act has a parallel commercial article (sections 26140 to 26145) covering disclosure on sale and an affirmative duty to assess mold after notice of chronic water intrusion. It carries the same delayed start.

Who inspects in Los Angeles County

Which office shows up depends on where the building sits.

Unincorporated County areas

The County’s Rental Housing Habitability Program covers rental properties in the unincorporated areas only, which includes Ladera Heights and View Park (see our Ladera Heights, View Park and Westchester page for which side of the line each is on). Its inspectors check for “lead and mold hazards” alongside pests, water, heat and structural damage. Each unit gets a routine inspection once every four years, and complaints go to DPH Environmental Health at 888-700-9995. The program says the inspector contacts the tenant within three days of a complaint and schedules an inspection within seven.

City of Los Angeles

Rental buildings of two or more units in the city are on the Systematic Code Enforcement Program cycle, and an unresolved order can lead to the Rent Escrow Account Program. Our guide to SCEP inspections and REAP covers the 30-day compliance period, extensions and what REAP does to rent.

Inglewood, Culver City and Beverly Hills

The state rules above apply in all three cities, and a tenant can bring in code enforcement in any of them. A pending repair complaint also affects the timing of any rent or tenancy change, which is where the retaliation rule below comes in. See our Inglewood, Culver City and Beverly Hills pages for each city’s rent and tenancy rules.

Handling a mold report, step by step

1. Log the date. Under section 1941.7 notice starts the duty, so write down when and how the report came in and reply in writing the same day.
2. Schedule entry properly. Give section 1954 notice unless the tenant agrees to an entry date within one week or there is an emergency, such as an active leak.
3. Find the water. The County’s guidance is that mold grows in damp places such as around leaky roofs, windows or pipes, or after flooding. A plumber or roofer who finds and fixes the source is the repair. Cleaning without that only resets the clock.
4. Size the cleanup. The County says that for a moldy area under about 10 square feet the job can be handled without a specialist, using soap and water or a bleach solution of no more than one cup of bleach per gallon of water, and that absorbent materials such as carpet and ceiling tiles may have to be replaced. For anything larger, anything inside a wall cavity, or anything tied to sewage or flooding, bring in a remediation contractor.
5. Photograph before, during and after, and keep the vendor’s written description of the cause and the work done.
6. Check back. A follow-up visit a few weeks later, with notice, shows whether the moisture source is really fixed and gives you a dated record that it was.
7. Tell the tenant what was done, in writing, including anything you are asking of them, such as running the bathroom fan.

Who pays, and the retaliation window

When the cause is a building condition, the repair is the owner’s. When the cause is the tenant’s conduct under section 1941.2, the repair duty under 1941.7 does not arise, but the unit still needs fixing before the next tenant, and the question becomes recovery. Civil Code section 1950.5(b) allows a security deposit to cover repair of damage caused by the tenant or a guest, “exclusive of ordinary wear and tear,” and cleaning needed to return the unit to the level of cleanliness it had when the tenancy began. A deduction for mold needs the same proof as any other: move-in condition, cause and cost. Our guides to the security deposit rules and move-out inspections cover the itemization.

Then the timing rule. Under Civil Code section 1942.5, if a tenant who is not in default on rent has given good-faith notice of a repair problem, complained to a government agency, or had an inspection or citation result, the owner may not, in retaliation, recover possession, cause the tenant to leave involuntarily, raise rent or reduce services within 180 days. A rent increase or nonrenewal notice served weeks after a mold complaint invites exactly that claim. Finish the repair, document it, and plan any rent or tenancy change with the 180-day window in view.

Questions owners ask

Do I have to test for mold when a tenant reports it?

No. Section 26147(b) says a residential landlord is not required to conduct air or surface tests, and both the state and County health departments say testing is not needed to decide what to do about visible mold. Find the moisture source and fix it.

The tenant’s lab report says the spores are toxic. Does that change anything?

California has no exposure limit to measure it against, and the state department says the particular kind of mold does not matter. What counts under section 17920.3 is visible growth as determined by a health officer or code enforcement officer. Treat the report as a sign that the tenant is worried and respond to the condition, in writing.

Is mold in the shower grout a habitability problem?

Paragraph (13) excludes mold that is minor and found on surfaces that can accumulate moisture as part of their intended use. Small spotting on grout is the kind of thing that exclusion describes. Mold spreading onto the ceiling or into drywall is a different question, and a bathroom fan that does not work is a repair in its own right.

Do I have to give new tenants a mold disclosure?

The statutes that call for one, sections 26147 and 26148, are written so they do not apply until the state health department adopts standards or approves a booklet, and the department says exposure limits do not exist. Giving tenants the department’s mold information anyway is cheap insurance. Confirm your lease package with a real estate attorney.

Can I charge the tenant for mold cleanup?

Only for damage the tenant caused, beyond ordinary wear and tear, or cleaning needed to return the unit to its move-in condition, and only with evidence of cause and cost. Mold from a leak, a failed seal or a missing fan is a building repair.

Sources and disclaimer. California Health and Safety Code sections 17920.3, 26101, 26103, 26105, 26143, 26147 and 26148; California Civil Code sections 1941.7, 1941.2, 1942, 1942.5, 1950.5 and 1954; California Department of Public Health, Frequently Asked Questions about Mold; Los Angeles County Department of Public Health, Mold in the Home and Rental Housing Habitability Program FAQ. Current as of October 2026. This article is general information for property owners from a California DRE-licensed property management company, not legal advice. Confirm your obligations on a specific unit with a real estate attorney before relying on a disclosure position, a deposit deduction or a change to a tenancy after a repair complaint.