What Rental Property Owners and Managers Need to Know About the New Substandard Housing Mold Law


Governor Brown signed a bill into law effective on January 1, 2016, which states that under certain conditions the presence of “visible mold growth” that endangers the life of occupants in a residential rental could be considered a substandard housing condition. The precise language requires ALL of the following to be true:

There is “visible mold growth” (as opposed to any mold located on any surface) that “endangers the life, limb, health, property, safety or welfare ... of the occupants” unless the presence of that mold is minor and is found “on surfaces that can accumulate moisture as part of their properly functioning and intended use” (e.g. bathroom exhaust fan).

A property owner’s obligation to repair the moldy condition arises only where the rental property owner or manager has notice from the tenant of the dilapidation due to the presence of actual and visible mold growth. Additionally, the law affirmatively requires tenants to maintain the property in a clean and sanitary fashion. This obligation may be used by a property owner defending against a substandard housing citation involving an allegation that the property has visible mold growth.

This Q&A explains California’s new mold law, and how property owners and managers can protect their properties from being cited as “substandard.”

1. Overview of the new mold law.

In general, the new law makes the existence of unhealthy levels of mold under certain conditions a substandard housing condition. As it is with any substandard housing condition, property owners can be fined, cited, and sued. The new law creates a new specific category of substandard housing (mold) and places obligations to perform on property owners and tenants regarding the repair of dilapidation and the maintenance of rental property.

Conditions that give rise to unhealthy levels of molds like damp walls and floors have long been established as substandard housing conditions. (Health and Safety Code Section 17920.3) Moreover, landlords have always been under a duty to maintain their properties in a safe and sanitary way. (Civil Code Section 1940 et seq.)

The new law states that mold, under certain conditions, can be considered a substandard housing condition. Specifically, the new law states that a substandard mold condition exists if mold is visible and endangers the life of occupants or public in a dwelling unit as determined by a local government code enforcement officer.

The law also contains exceptions and protections for property owners. Mold that is minor and found on surfaces that normally accumulate mold or moisture as part of its regular function—like bathtubs and showerheads and exhaust fans—does not create a substandard housing condition. Moreover, the new law very clearly states that property owners are under no duty to repair dilapidations caused by mold problems if they have not received notice about the problems, or if the tenant caused the mold problem by breaching any of his affirmative obligations to maintain his or her premises in a clean and sanitary manner under California Civil Code 1941.2.

Accordingly, if a tenant’s failure to properly maintain his or her dwelling caused the mold problem, a property owner should not be cited for a substandard housing condition. It should be noted, however, that regardless of who or what caused the mold problem, once the property owner knows about the issue, he or she has a duty to address the moldy condition promptly.


2. What happens if a dwelling is found to be substandard?

California’s substandard housing laws exist to ensure tenants have a safe, healthy and habitable dwelling unit within which to live. The substandard housing laws establish a list of conditions that, if they exist in a dwelling to an extent that endangers the life, limb, health, property, safety or welfare of the public or the occupants, make the unit unhealthy, unsafe and unfit for tenants to live in. Examples of substandard housing conditions include lack of proper bathrooms and showers, lack of proper ventilation, and lack of adequate heating and lighting. The list is extensive. (See Cal. Health and Safety Code 17920.3 for a list of all substandard housing conditions.) When a substandard housing condition exists—for example, if water is not properly running—a landlord not only violates California’s substandard housing laws, he or she is also in violation of the implied warranty of habitability. The consequences can be substantial:

  • A landlord can be ordered to repair the condition immediately.
  • Fines, citations and fees can be in the thousands.
  • Legal costs and repair costs can be in the tens of thousands.
  • A lien on the property can be placed by the city.
  • In the most severe case, a landlord who repeatedly violates substandard housing laws can be placed in jail for up to a year in some jurisdictions.
  • In Los Angeles, there is a program called "REAP” that allows the City to take over as manager, cut rents in half, and use the other half of rent to pay contractors to make the needed repairs.
  • The landlord can lose his ability to write off any deductions from his State taxes.
  • Tenants can withhold rent.
  • Tenants can sue.
  • Tenants can defend against evictions.
  • Tenants can receive many months of free rent.
  • Depending on the severity of the substandard housing condition, landlords may have to pay for a tenant’s temporary relocation costs.
  • Where the building requires major rehabilitation to satisfy the order, some jurisdictions require the landlord to pay for lodging, meals and other temporary expenses while the construction is under way.
  • A property owner can be liable to a tenant for attorney’s fees and costs, actual damages, and special damages of up to $5,000 for demanding or collecting rent, increasing rent, or attempting to evict a tenant when a substandard housing condition exists. (See Civil Code 1942.4(a)(3).)

3. What is mold, and why has California made mold (under specific conditions) a substandard housing condition?

Mold for the purposes of this law is defined as microscopic organisms or fungi that can grow in damp conditions in the interior of a building. The Centers for Disease Control and Prevention describe mold as follows:

Molds are fungi that can be found both indoors and outdoors. No one knows how many species of fungi exist but estimates range from tens of thousands to perhaps three hundred thousand or more. Molds grow best in warm, damp and humid conditions, and spread and reproduce by making spores. Mold spores can survive harsh environmental conditions, such as dry conditions, that do not support normal mold growth … Mold can cause fungal allergy and respiratory infections or worsen certain illnesses such as asthma. Molds are microorganisms that are found virtually everywhere, indoors and outdoors. The potential health effects of exposure to indoor mold are of increasing concern.

Some people are sensitive to molds. For these people, exposure to molds can cause symptoms such as nasal stuffiness, eye irritation, wheezing or skin irritation. Some people, such as those with serious allergies to molds, may have more severe reactions. Severe reactions may occur among workers exposed to large amounts of molds in occupational settings, such as farmers working around moldy hay. Severe reactions may include fever and shortness of breath. Some people with chronic lung illnesses, such as obstructive lung disease, may develop mold infections in their lungs.

California’s new mold law was enacted to address serious health concerns that mold may cause tenants, given certain and specific reasons and processes that the parties must follow.


4. When is the presence of mold a substandard housing condition?

The standard under the new law for what constitutes a substandard housing condition is as follows:


  • The mold must be visible growth;
  • A code enforcement officer must determine that the mold growth endangers the life, limb, health, property, safety or welfare of the public or the occupants;
  • The mold cannot be “minor and found on surfaces that can accumulate moisture as part of their properly functioning and intended use.”

Note, however, a tenant has an affirmative duty under Civil Code Section 1941.2. Specifically, the new law states:

An obligation shall not arise under Section 1941 or 1942 to repair a dilapidation relating to the presence of mold pursuant to paragraph (13) of subdivision (a) of Section 17920.3 of the Health and Safety Code (the amendment to the substandard housing law relating to visible mold growth) until the lessor has notice of the dilapidation or if the tenant is in violation of Section 1941.2.

Additionally, the tenants must keep the premises clean and sanitary. (See Civil Code Section 1941.7(a))

Those tenant duties under Section 1941.2 include the following:

  • Keeping the premises clean and sanitary as the condition of the premises permits (emphasis added).
  • Using and operating gas, electrical and plumbing fixtures properly. (Examples of improper use include overloading electrical outlets; flushing large, foreign objects down the toilet; and allowing any gas, electrical or plumbing fixture to become filthy.)
  • Disposing of trash and garbage in a clean and sanitary manner.
  • Not destroying, damaging or defacing the premises, or allowing anyone else to do so.
  • Not removing any part of the structure, dwelling unit, facilities, equipment or appurtenances, or allowing anyone else to do so.
  • Using the premises as a place to live, and using the rooms for their intended purposes. (For example, the bedroom must be used as a bedroom, and not as a kitchen.)
  • Notifying the landlord when the dead bolt locks and window locks or security devices don’t operate properly.

5. When is mold dangerous to “life, limb, health, property, safety, or welfare of the public or the occupants?”

Ultimately, a code enforcement officer determines when a mold condition rises to a level that is dangerous to humans. The CDC states that a good indicator that a mold problem exists is when you have “large mold infestations” that “can usually be seen or smelled.”

Other tips to detect dangerous molds:

  • Check for visible signs of mold growth. Their cotton-like features that appear in colors such as gray, black, white or green characterize molds.
  • Use your sense of smell. Sometimes molds can be detected because they smell.
  • Look for damp conditions. If a water pipe recently broke, or a flooding occurred (toilet overflow, refrigerator problem, plumbing problem, rain storm, etc.), it is possible mold might be growing somewhere in the unit.
  • Windows mist over during the winter. Winter season is characterized by rain and cold. When it’s cold and rainy, there is excess moisture. This excess amount of humidity in the environment can cause fungal growth, which culminates the most in damp areas.
  • Some people use home mold test kits. Mold testing is used to find out any dangerous threats of molds. These do-it-yourself test kits are designed to track down the presence of harmful molds that can trigger serious health problems. Most of these testing devices are user-friendly and can provide reliable results.
  • Despite your efforts, molds can be hidden. Most experts agree that the most perilous mold is the one that is unseen, such as in air conditioning units, ductwork or within walls. These molds can swell up rapidly while undetected. In most cases, hidden molds can be discerned not by eye but by the stale odor or the frequent need to clear your throat. Proper care and maintenance will typically prevent these.
  • Hire a certified mold inspector. In instances where you cannot detect if there are visible molds inside your house, some owners have used licensed mold inspectors and mold remediators.

6. When is mold “minor and found on surfaces that accumulate moisture as part of their properly functioning intended use”?

The term “minor” is undefined in the statute. That means common sense must apply.

Surfaces that accumulate moisture as part of their properly functioning intended use are going to be surfaces like shower areas, showerheads, toilets, sinks, windows and refrigerators. Anything that typically accumulates moisture will qualify.

So, if there is just a little amount of mold on such a surface, a property owner will likely not be cited for having a substandard housing condition.


7. What are the property owner’s duties?

Ultimately, a property owner must ensure that unhealthy levels of mold do not accumulate in his or her dwelling units. Maintenance that involves checking for mold could become part of a property owner’s regular duties. Although tenants will have a duty to keep their units clean and sanitary, and will need to report unhealthy mold growths that they become aware of, property owners always maintain a duty of maintenance, and will need to address mold problems when they learn of them.

The information provided herein is intended to give general guidance and awareness on SB 655 and shall not be construed in any way as a substitute for individual legal advice. Those that require specific advice should consult an attorney.

To obtain a copy of the new law, please see SB 655, Chapter 720, and Statutes of 2015 at: Leginfo.ca.gov. Ron Kingston can be reached at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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