Indoor Air Quality in Rental Dwellings

State Laws Addressing Radon, Mold and Secondhand Smoke


Part I: Background


With nearly one-third of the nation’s housing units occupied by renters, state policy makers can advance healthy housing goals by strengthening their laws and regulations that establish minimum conditions in rental housing. Rental housing laws are particularly important to reducing indoor exposure to air pollutants for vulnerable populations. Recent Census data show that there are more renter-occupied households than owner-occupied households with incomes below $50,000. See U.S. Census Bureau, 2018 American Community Survey .

Two common types of policies that address indoor environmental conditions in rental housing are housing codes and landlord-tenant laws. Housing codes (also known as sanitary or property maintenance codes) establish minimum conditions and maintenance requirements for rental properties and are usually enforced by local housing or health agencies. Though typically adopted by local governments, some states have established housing codes that set statewide requirements. Landlord-tenant laws set forth the rights and responsibilities of landlords and tenants, including responsibility for maintaining the premises. Unlike housing codes, these laws are typically enforced privately. They provide legal recourse for landlords and tenants to address violation of the laws, including the failure to remedy substandard housing conditions.

While these policies differ from state to state, many are based on model codes and include certain basic provisions for preventing and fixing unhealthy or dangerous conditions. They generally require landlords to maintain the premises and may require that units be kept in “habitable” condition, or in “good repair” so as not to endanger the health and safety of tenants. The effectiveness of such general provisions in addressing specific IAQ issues depends on a range of factors, including the precise language of the statute or regulation, the enforcement priorities and resources of local agencies, and the resources available to tenants to pursue a claim. A 2003 ELI report discusses how local jurisdictions have used their housing laws to respond to IAQ problems.

Rental housing laws and regulations can address known health risks more directly by establishing clear requirements relating to specific indoor pollutants. Policymakers have been active in tackling certain IAQ issues in the rental housing context—e.g., lead-based paint abatement and installation of carbon monoxide alarms. State law is less developed with respect to other important indoor pollutants. Part II discusses three of these pollutants—radon, mold, and secondhand smoke—and state legislation that has been adopted to date. Check back for updates as new laws are enacted.

See also ELI's 2017 Indoor Air Quality Guide for Tenants.


Part II: State Laws on Mold, Radon and Secondhand Smoke



Indoor exposure to mold and dampness can produce a variety of health effects, including respiratory problems (wheezing, difficulty breathing, shortness of breath); cough; nasal or sinus congestion; eye, nose, throat or skin irritation; and asthma symptoms in people with asthma. Remedial action is generally warranted if you can smell or see mold or dampness—testing is typically not required or recommended. See National Institute of Medicine, Damp Indoor Spaces and Health (2004); Cal. Dept. of Public Health, Statement on Building Dampness, Mold and Health (2011). Because mold can grow almost anywhere provided that moisture and oxygen are present, mold remediation involves both cleaning up the mold and fixing the underlying water condition that facilitated the mold growth and dampness. Important steps for preventing mold growth include maintaining acceptable humidity levels and cleaning up water leaks or spills quickly—generally within 24-48 hours. See US EPA, A Brief Guide to Mold, Moisture and Your Home.

State Laws. State housing codes and landlord-tenant laws commonly include some provisions that address the underlying dampness and moisture problems that cause mold contamination—e.g., requirements for: damp-free building components; adequate ventilation (generally and/or in bathrooms and kitchens); adequate plumbing (fixtures maintained in good working order, free from leaks); weathertightness (structural components maintained to prevent moisture intrusion); and non-absorbent surfaces (bathroom, kitchen surfaces impervious to water).

Legal provisions such as these can be important to ensuring the correction of defects that cause mold and dampness. Most codes do not, however, explicitly mention “mold” or require mold cleanup. At least five states and the District of Columbia have enacted state legislation establishing explicitly a landlord’s duty to prevent and address mold contamination as part of the landlord-tenant law or building/sanitary code. Though not included here, municipal housing codes may also address mold in rental housing. For example, New York City recently enacted the Asthma Free Housing Act (2018/055) amending the city’s housing maintenance code to require private landlords to prevent and remediate indoor allergen hazards, including mold and pest infestation.

For a discussion of these and other state laws addressing mold and dampness in rental housing, see ELI's 2017 report on IAQ and Climate Change (chapter 3).



Radon is a naturally-occurring, radioactive gas produced by the breakdown of uranium in soil, rock, and water. Indoor exposure to radon is the second leading cause of lung cancer in the United States and the leading cause of lung cancer among non-smokers. According to the U.S. EPA, indoor radon exposure is responsible for about 21,000 lung cancer deaths in the U.S. each year, with nearly 3,000 deaths among people who have never smoked.

The concentration of radon in indoor air is affected by the way homes are constructed. EPA has established a radon “action level” of 4 picoCuries/liter (pCi/L)—the level at which a building owner should take action to reduce radon in the indoor air. However, because there is no known safe level of exposure to radon, EPA also recommends that people consider fixing their home when radon levels are between 2 pCi/L and 4 pCi/L. Elevated indoor radon levels can exist in all parts of the U.S., and the only way to know the radon level in a particular home is to test the home for radon. If testing reveals elevated levels, there are well established, cost-effective methods for installing radon reduction systems. See,

State Laws. While general habitability and good repair provisions found in housing codes and landlord-tenant laws are potentially relevant to situations where tenants are exposed to elevated radon levels, they may not provide a strong foundation for effective public enforcement or private (tenant) legal action to reduce elevated radon levels. A few states have laws that address the subject of radon in rental housing directly, though they are not necessarily strong models for state legislation. The state of Maine requires landlords to test for and disclose radon levels in their properties. In Illinois, the law requires landlords to disclose known elevated radon levels. Florida law requires that all rental agreements include a notification regarding the health risks of radon.

Though not discussed here, municipal codes may also address radon in rental housing. For example, a 2019 Iowa City, Iowa ordinance requires single-family and duplex rental homes to be tested for radon and retested every eight years; if tests are 4.0 pCi/L or higher, a mitigation system must be installed. South Brunswick Township, New Jersey, is another municipality that has adopted an ordinance requiring a landlord to provide a completed radon test with concentrations below 4.0 pCi/L prior to renting a dwelling unit. In 2022, Montgomery County (MD) enacted an ordinance requiring landlords to test for radon in their rental housing, disclose testing results to tenants, and mitigate if radon levels are at or above 4.0 pCi/L.

There also may be state or local laws that address the subject of radon in residential drinking water wells. For example, a Connecticut law authorizes local directors of health to require a private residential well to be tested for radon if located in a geological area known to have naturally-occurring radon or located in an area known to have radon in the groundwater. The same law requires that the owner of a property on which a residential well is located must, prior to rental, provide the tenant notice that educational material concerning private well testing is available on the state Department of Public Health website.


Secondhand Smoke

Secondhand smoke (environmental tobacco smoke) contains over 250 carcinogenic or toxic chemicals and causes about 3,400 lung cancer deaths and 46,000 heart disease deaths among nonsmokers each year. National Toxicology Program, 13th Report on Carcinogens (2014); Centers for Disease Control and Prevention, Secondhand Smoke. Children exposed to secondhand smoke face an increased risk for sudden infant death syndrome (SIDS), acute respiratory infections, ear infections, and more severe asthma symptoms. Office of the Surgeon General, The Health Consequences of Involuntary Exposure to Secondhand Smoke (2006).

According to the U.S. Surgeon General, the scientific evidence is sufficient to conclude that there is no risk-free level of exposure to secondhand smoke. Office of the Surgeon General, A Report of the Surgeon General: How Tobacco Smoke Causes Disease . “Eliminating smoking in indoor spaces fully protects nonsmokers from exposure to secondhand smoke. Separating smokers from nonsmokers, cleaning the air, and ventilating buildings cannot eliminate exposures of nonsmokers to secondhand smoke." Health Consequences at 11. Thus, even if a tenant does not smoke, he or she may still risk exposure to secondhand smoke that seeps through shared walls, ventilation systems, windows, and doors.

In December 2016, HUD adopted a new rule that requires all public housing agencies (PHAs), by July 30, 2018, to adopt a smoke-free policy. The rule applies to all public housing units, interior areas, and outdoor areas within 25 feet of the housing.

State Laws. In general, state housing codes do not address directly the issue of secondhand smoke and thus do not provide a strong foundation for code enforcement in cases where tenants are harmed by drifting smoke. Some of the broad provisions contained in state landlord-tenant laws may provide a basis for legal action by tenants in certain cases.

A number of municipalities (primarily in California) have enacted ordinances prohibiting or significantly restricting smoking in multi-family housing. At the state level, a number of states that have enacted laws banning smoking in public places have included in these laws a ban on smoking in common areas in multi-family residential buildings. Following are three examples of this type of law (there are a number of other states with similar prohibitions); the Colorado and Minnesota no-smoking requirements apply to marijuana smoking as well. Note that this approach does not address exposure resulting from smoking within individual rental units.

The state of Utah has enacted a nuisance law that defines drifting smoke as a nuisance. This strategy may provide tenants with legal recourse in certain circumstances.

At least three states have enacted laws that require disclosure of a building’s smoking policy. This strategy may encourage prospective tenants to consider potential exposure to second-hand smoke and may indirectly encourage property owners to adopt no-smoking policies. In addition, California's landlord-tenant law affirms a landlord's right to prohibit smoking and requires notice to tenants of any smoking ban.

In addition to policies governing existing multifamily properties, states can require no-smoking policies in housing that is to be constructed with government financing. For example, the State Housing Authority in Maine has adopted rules that require recipients of the Low Income Housing Tax Credit to “implement a written occupancy policy prohibiting smoking in the units and common areas...include a non-smoking clause in the lease for every household...and...make educational materials on tobacco treatment programs...available to all tenants through the resident service coordinator." 99-346 Code of Maine Rules Ch. 16, §5.


Last Updated: April 2021

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