Indoor Air Quality in Rental Dwellings

State Laws Addressing Radon, Mold and Secondhand Smoke



Around one-third of the nation’s housing units are occupied by renters. Policy makers can reduce indoor air risks and create healthier and more resilient housing by strengthening laws and regulations that establish minimum housing conditions. Rental housing standards that reduce indoor pollutant exposures are especially important for households with limited affordable housing options. According to 2022 U.S. Census data, households that rent their homes have considerably lower annual income on average than owner-occupied households. A 2020 Government Accountability Office report found that “[h]ouseholds with low incomes…or with rent burdens comprised half or more of renters living in units with substantial quality issues…”

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. Housing codes are typically adopted by local governments, though some states have established statewide housing codes. Landlord-tenant laws are adopted at the state level and set forth the rights and responsibilities of landlords and tenants, including the responsibility to maintain the premises. Unlike housing codes, landlord-tenant 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 housing codes and landlord-tenant laws differ from state to state, many are based on model codes. The policies commonly require units to be kept in “habitable” condition or in “good repair.” Such general provisions could potentially be used to remedy unhealthy conditions and harmful indoor air exposures, but policymakers can address known health risks more directly and effectively by establishing clear requirements relating to specific indoor environmental conditions. Some states and local governments, for example, have adopted housing codes, landlord-tenant laws, and other policies requiring landlords to address lead-based paint hazards or to install carbon monoxide alarms.

This policy brief highlights state rental housing policies that address three other important indoor pollutant exposures – radon, mold, and secondhand smoke.

See also ELI's 2017 Indoor Air Quality Guide for Tenants, which offers a starting point for tenants to learn more about IAQ in their homes.


Mold in Rental Housing: Selected State Policies

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 U.S. 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).

In addition to the above examples, the state of Washington' health and labor rules for temporary worker housing for agricultural employees require operators of the housing to prevent mold in dwelling units and common facilities and to meet certain filtration standards for mechanical ventilation systems. See Wash. Admin. Code 296-307-16145--16146; 246-358-075--076. 


Radon in Rental Housing: Selected State Policies

Radon is a radioactive gas that is found in soil and rock and can enter buildings through cracks and other openings in the foundation. Indoor exposure to radon is the second leading cause of lung cancer in the U.S. 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. U.S. EPA, Health Risk of Radon.

Elevated indoor radon levels have been found 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. EPA has established a radon “action level” of 4 picoCuries/liter (pCi/L), but the agency also recommends that people consider fixing their home when radon levels are between 2 pCi/L and 4 pCi/L. U.S. EPA, A Citizen’s Guide to Radon.  There are well established, cost-effective methods for installing radon reduction systems. U.S. EPA, Radon-Resistant Construction Basics and Techniques.

Few states have laws that address the subject of radon in rental housing directly. The state of Maine requires landlords to test for and disclose radon levels in their properties. Laws in Illinois and Colorado require landlords to provide radon information to tenants and allow tenants to end the tenancy in certain situations involving elevated radon levels. Florida law requires that all rental agreements include a short statement on the health risks of radon. States can build on these examples and establish stronger radon protections by requiring rental housing owners to test for radon and to mitigate elevated radon levels. 

A 2012 ELI report discusses key components of a policy addressing radon in rental housing.

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.


Secondhand Smoke in Rental Housing: Selected State Policies

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). Note that this approach does not address directly 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.


Policies Last Updated: Dec. 2023

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