In the early 1970s, in response to growing concerns about the housing conditions of poor families, the US Department of Housing and Urban Development (HUD) developed a measure of housing adequacy for its American Housing Survey (AHS)that continues to be used by the agency today. This adequacy measure was originally designed to evaluate the extent to which the national housing stock met the standard of “a decent home and a suitable living environment” established by the Housing Act of 1949. While the condition of the housing stock has improved over the past several decades, the rental stock is still three times more likely than the owner-occupied stock to be considered inadequate. And problems persist among the most affordable rentals.

While fairly complex, the AHS adequacy measure factors in various housing problems related to plumbing, heating, electrical wiring, and maintenance. Using this AHS measure, the majority of the nation’s rental housing stock is in physically adequate condition. As of 2013, just 3 percent of occupied rental units were categorized as severely inadequate and 6 percent were moderately inadequate. In fact, the adequacy of the rental stock has improved over the past decade, with the share of rentals categorized as physically inadequate declining from about 11 percent in 2003 to 9 percent in 2013.

Stricter building codes have certainly helped to encourage higher quality, particularly the construction of units with complete plumbing and heating systems. As a result, severe physical deficiencies have been rare among the rental stock, especially among newer rentals. Just 1 percent of rentals built 2003 and later was classified as severely inadequate, compared to 4 percent of those built prior to 1960.

It is noteworthy, however, that the AHS adequacy measure does not account for certain health-related quality issues such as the presence of mold or structural issues such as holes in the roof or foundation, so housing quality problems may in fact occur at higher rates than the survey reports. And although physical deficiencies have become less common among the nation’s rental housing stock, housing problems disproportionately appear in units occupied by the lowest-income renters. In 2013, 11 percent of units occupied by extremely low-income renters (those with incomes less than or equal to 30 percent of area medians) were physically inadequate, compared to just 7 percent of those with incomes above 80 percent of area medians.

The lowest-income households also accounted for the largest share of renters reporting overcrowded conditions and physical housing problems such as toilet breakdowns, exposed electrical wiring, heating equipment breakdowns lasting six hours or more and the presence of rats in the unit.

Matthew Desmond’s most recent book, Evicted, vividly captures these statistics, drawing attention to the grim housing conditions of families in low-rent units in inner-city Milwaukee who must live with the constant presence of roaches and other vermin, clogged sinks and bathtubs, holes in their windows, and broken front doors.Rentals occupied by extremely low-income households in central cities have the highest physical inadequacy rates, especially those located in small multifamily buildings with 2-4 units. Indeed, 16 percent of these units were categorized as inadequate, compared to 12 percent of those in buildings with 50 or more units. As I pointed out in a previous post, small multifamilies are a critical source of low-cost housing because they tend to charge lower rents than those in much larger structures, but much of this stock is rather old and at higher risk of loss from the affordable stock due to deterioration.As this recent NPR piece suggests, the narrow margins for mom-and-pop landlords operating in low-income neighborhoods do not provide sufficient incentive for landlords to make improvements or repairs in a timely manner. Indeed, according to the American Housing Survey, 13 percent of extremely low-income renters reported in 2013 that the owner of their unit usually did not start major repairs or maintenance quickly enough, compared to less than half that share (6 percent) among higher-income renters with incomes above 80 percent of area medians.

The prevalence of housing deficiencies among units occupied by the lowest-income renters highlights the importance of bolstering building code enforcement efforts at the state and local levels. However, municipalities are often faced with tight budgets that lead to dwindling code enforcement teams. Indeed, according to one estimatein 2013, Cleveland and Detroit, among others, have cut their code enforcement workforce by about half since the middle of the last decade. Cities like Baltimore, Portland, and the San Francisco Bay Area are also facing shortages of building inspectors that make it difficult to deal with building code violations. While increased code enforcement can identify landlords who are failing to maintain their properties, this could also lead to unstable housing situations for current tenants. Renters may withhold rent or call local building inspectors as a tactic to push landlords to make necessary repairs, but this could lead to eviction threats or the initiation of a formal eviction process due to nonpayment of rent.

At the federal level, budgetary constraints have also impacted efforts to address the physical deficiencies among the aging public housing stock, which was largely built before 1970. Federal appropriations for the public housing capital fund fell by 34 percent over the past decade and HUD is faced with an estimated backlog of $26 billion in capital maintenance and repairs (as of 2010). HUD’s housing choice voucher and project-based rental assistance programs, which subsidize rentals for low-income households in the private market, require landlords to pass annual or biennial inspections for housing quality. However, the public housing stock is not subject to regular inspections and has largely been prohibited from using private capital to finance capital needs and repairs. As a result, compared to other types of assisted rentals, physical housing problems are more common among the public housing stock. In 2013, over half (53 percent) of public housing units had more than two heating equipment breakdowns lasting at least six hours and 13 percent of units had water leaks due to equipment failures within the previous 12 months.

Living in unsafe, physically inadequate housing can lead to adverse health and developmental outcomes for low-income families. Indeed, recent research confirms that children exposed to defects such as leaking roofs, broken windows, rodents, and nonfunctioning heaters or stoves were more likely to experience emotional and behavioral problems. Among five housing characteristics studied—quality, stability, affordability, ownership, and receipt of housing assistance—poor physical quality of housing was the most consistent and strongest predictor of emotional and behavioral problems in low-income children and adolescents. Poor housing conditions such as mold, chronic dampness, water leaks, and heating, plumbing, and electrical deficiencies, are also associated with health risks like respiratory illness and asthma. These findings underscore the urgent need for cities to prioritize code enforcement and work collaboratively with nonprofit tenants’ rights groups to deal with landlords who are not responsive to requests for necessary repairs.