Supporting Documentation

NCHH created the rating system using American Housing Survey data collected after 1997. The report covers 45 metropolitan statistical areas and includes two indicators. The first indicator, called “Healthy Housing,” compares 20 housing conditions that are linked with health problems to national averages for those conditions. It is the first national indicator of healthy housing and includes variables such as the presence of rats and mice, the presence of interior and exterior leaks, and electrical and heating problems. The second indicator is “Basic Housing Quality” and is based on the AHS measure of housing with severe and moderate physical problems. It includes primarily structural problems such as inadequate plumbing or kitchen facilities, crumbling foundations, and damaged roofs.

Executive Summary
Key Definitions of the Characteristics Used in the Report
Frequently Asked Questions
Evidence Table

Key Definitions of the Characteristics Used in the Report

Holes in floors. Respondents were asked about holes in the interior floors of the unit. The holes may or may not go all the way through to a lower floor or to the exterior of the unit. The holes are only counted if large enough for someone to trip in.

Open cracks or holes (interior). Statistics are presented on open cracks or holes in the interior wall or ceilings of the housing unit. Included are cracks or holes that do not go all the way through to the next room or to the exterior of the housing unit. Hairline cracks or cracks that appear in the walls or ceilings but are not large enough to insert the edge of a dime, are not counted. Very small holes caused by nails or other similar objects are also not counted.

Broken plaster or peeling paint (interior). The area of peeling paint or broken plaster must be on the inside walls or ceilings and at least one area of broken plaster or peeling paint must be larger than 8 inches by 11 inches.

Signs of mice or rats. The statistics on signs of mice or rats refer to respondents who reported seeing mice or rats or signs of mice or rats inside the house or building during the three months prior to interview or while the household was living in the unit if less than three months. Signs of mice or rats include droppings, holes in the wall, or ripped or torn food containers.

Water leakage during last 12 months. Data on water leakage are shown if the leakage occurred in the 12 months prior to the interview or while the household was living in the unit if less than 12 months. Housing units with water leakage are classified by whether the water leaked in from inside or outside the building and by the most common areas (roof, basement, walls, closed windows, or doors) or reasons (fixtures backed up or over-flowed or pipes leaked) of water leakage.

Water supply stoppage. “Water supply stoppage” means that the housing unit was completely without running water from its regular source. “Completely without running water” means that the water system servicing the unit supplied no water at all; that is, no equipment or facility using running water (kitchen or bathroom sinks, shower, bath tub, flush toilet, dishwasher, and other similar items) had water supplied to it, or were all inoperable. The reason could vary from a stoppage because of a flood or storm to a broken pipe, to a shutdown of the water system, to a failure to pay the bill, or other reasons. Data on water stoppage are shown if they occurred in the three months prior to the interview or while the household was living in the unit if less than three months and if the breakdown or failure lasted six consecutive hours or more.

Flush toilet and flush toilet breakdowns. A privy or chemical toilet is not considered a flush toilet. Flush toilets outside the unit were not counted. The statistics on breakdowns of flush toilet are shown for housing units with at least one flush toilet for the household’s use only. The flush toilet may be completely unusable because of a faulty flushing mechanism, broken pipes, stopped up sewer pipe, lack of water supplied to the flush toilet, or some other reason. For households with more than one toilet, the question asked about times when all toilets were unusable.

Sewer disposal breakdown. The data on breakdowns in the sewage disposal are limited to housing units in which the means of sewage disposal was a public sewer, septic tank, or cesspool. Breakdowns refer to situations in which the system was completely unusable. Examples include the septic tank being pumped because it no longer perked, tank collapsed, tank exploded, sewer main broken, sewer plant not operating as result of electrical failure, or water service interruption. Data on breakdowns are shown if they occurred in the three months prior to the interview or while the household was living in the unit if less than three months and if the breakdown lasted six consecutive hours or more.

Lacking complete plumbing. The category ‘‘With all plumbing facilities’’ consists of housing units that have hot and cold piped water as well as a flush toilet and a bathtub or shower. For units with less than two full bathrooms, the facilities are only counted if they are for the exclusive use of the occupants of the unit. Plumbing facilities need not be in the same room. Lacking some plumbing facilities or having no plumbing facilities for exclusive use means that the housing unit does not have all three specified plumbing facilities (hot and cold piped water, flush toilet, and bathtub or shower) inside the housing unit, or that the toilet or bathing facilities are also for the use of the occupants of other housing units.

Heating equipment breakdown. Statistics are shown for housing units occupied by the householder during the winter prior to the interview and refer only to the main heating equipment. The data are classified by whether the housing unit was uncomfortably cold for 24 hours or more, the number of times equipment breakdowns occurred lasting six hours or more, and causes for the breakdowns. The heating equipment is broken down if it is not providing heat at its normal heating capacity through some fault in the equipment.

Room heater without flue. This refers to any room heater that burns kerosene, gas, or oil, and that does not connect to flue, vent, or chimney.

Exposed wiring in unit. A housing unit is classified as having exposed electric wiring if the unit has any wiring that is not enclosed, either in the walls or in metal or plastic coverings. Excluded are appliance cords, extension cords, chandelier cords, and telephone, antenna, or cable television wires.

Rooms without electric wall outlets. A housing unit is classified as having rooms without electric wall outlets if there is not at least one working electric wall outlet in each room of the unit. A working electric wall outlet is one that is in operating condition; that is, it can be used when needed. If a room does not have an electric wall outlet, an extension cord used in place of a wall outlet is not considered to be an electric wall outlet.

Lacking kitchen facilities. Lacking a kitchen sink, refrigerator, or cooking equipment (stove, burners, or microwave oven) inside the structure for exclusive use of the unit.

Roofing problems. Units with “Sagging roof,” “Missing roofing material,” or “Hole in roof” were classified as having Roofing Problems. A “sagging roof” is a critical defect indicating continuous neglect, or deep serious damage to the structure. Only roofs with substantial sagging were included. “Missing roofing material” includes rotted, broken, loose or missing shingles, tiles, slate, shake, and tin, caused by extensive damage from fire, storm, or serious neglect. “Hole in roof” occurs when the missing roof materials expose the interior of the unit directly to weather. Holes caused by construction activity were not counted unless the construction had been abandoned. Statistics do not include multiunit structures.

Siding problems. Units with either “Missing bricks, siding, or other outside wall material” or “Sloping outside walls” were classified as having Siding Problems. “Missing bricks, siding, or other outside wall material” applies to the exterior wall (including chimney) of the structure. Those defects may have been caused by storm, fire, flood, extensive neglect, vandalism and so forth. Materials may include clapboard siding, shingles, boards, brick, concrete, and stucco. The missing materials do not necessarily expose the interior of the unit directly to weather. Missing materials resulting from construction activity were not included unless construction had been abandoned. “Sloping outside walls” is a critical defect indicating continuous neglect or serious damage to the structure. Only walls with substantial sagging were included. Statistics do not include multiunit structures.

Window problems. Units with either “Broken windows” or “Boarded up windows” were classified as having Window Problems. ”Boarded up windows” have been sealed off to protect against weather or entry and include windows and/or doors covered by board, brick, metal, or some other material. “Broken windows” indicated several broken or missing window panes. Statistics do not include multiunit structures.

Foundation problems. This category includes large cracks, holes, and rotted, loose, or missing foundation material. Statistics do not include multiunit structures.


Frequently Asked Questions

Which metropolitan areas have the most healthy and least healthy housing conditions?
Best MSA: The metro areas of San Jose, CA: Indianapolis, IN; Tampa-St Petersburg-Clearwater, FL; Anaheim-Santa Ana, CA; and Phoenix, AZ. Worst MSA: The metro areas of Memphis, TN; Birmingham, AL; San Antonio, TX; and Oklahoma City, OK.

Which central cities have the most healthy and least healthy housing conditions?
Best central cities: San Jose, CA; Fort Worth-Arlington, TX, Phoenix, AZ, San Bernardino-Riverside and San Diego, CA, have the healthiest housing.
Worst central cities: Birmingham, AL, and Detroit, MI, have the least healthy housing.

How were the data for the study collected?
The study uses data from the American Housing Survey (AHS), which is conducted by the U.S. Bureau of the Census for the U.S. Department of Housing and Urban Development. The results and details are available at The AHS collects the following data:
  • Individual household characteristics
  • Owner/renter’s income
  • Housing and neighborhood quality
  • Housing costs
  • Equipment and fuels
  • Size of housing unit
  • Recent moves.
National data are collected in odd-numbered years, and data for a subset of the nation’s Metropolitan Areas are collected approximately every two years. The AHS returns to the same housing units to gather data, while regularly adding units to represent new construction. The stated goal of the U.S. Department of Housing and Urban Development (HUD) is to sample each of the 46 Metro areas every six years, but because of budget constraints, some areas have not been sampled in over 10 years. The years of the Metro surveys included in this report are: 1998, 2002, 2003, 2004, 2007, 2009 and 2011. The survey includes apartments, single-family homes, mobile homes, and vacant homes; for this report, data were limited to occupied dwellings.

Why isn’t my city listed?
The U.S. Census Bureau produces a Metro Edition of the American Housing survey for a subset of 46 of the nation’s larger Metropolitan Statistical Areas, which are the same metro areas we cover in our rankings. Rochester NY, which has not been sampled since 1998, is not included in the rankings because the data is more than 15 years old. All other Metro areas were sampled in 2002 or more recently.

Why aren’t serious problems like cockroaches, missing/inoperable smoke alarms, scalding hot water, and other housing problems ranked?
The AHS does not have questions for every housing hazard, such as cockroaches, but we used as much of the data collected as we could. An overarching goal of the State of Healthy Housing is to increase interest and understanding of housing-related health hazards and to increase the size and scope of the American Housing Survey, which is the source of data for the study. We are advocating for increased funding for AHS to (1) include additional health-related questions in the survey, (2) ensure that the surveys are conducted according to the schedule set by HUD, and (3) to ensure that sufficient data are collected from each jurisdiction to enable rigorous analysis.

What’s the difference between the “Basic Housing” and the “Healthy Housing” Indicators?

“Basic Housing” covers the basic structure and systems that provide the minimally acceptable functions of housing, including plumbing, heating, electrical, kitchen, hallways, and upkeep. The score is the percent of homes with severe or moderate physical housing problems. Severe and moderate physical problems are defined by AHS. See Table 1 below for more information.

“Healthy Housing” assesses specific, significant health and safety hazards in the home, such as signs of rats, inoperable toilets, and peeling paint (a major factor in childhood lead poisoning). Twenty housing characteristics make up the healthy housing indicator.

How are the “Basic Housing” rankings calculated?
To assess basic housing quality, NCHH ranks each community by the percentage of homes with severe or moderate housing problems. If the percentage of severe or moderate housing problems for a community is statistically significantly different than the concurrent national percentage, the community is designated as Most Healthy or Most Unhealthy.

How are the “Healthy Housing” rankings calculated?
The Healthy Housing rankings were developed using a composite score of the 20 healthy housing characteristics. For every community, the 20 housing characteristics are assigned a value of -1 (significantly better than concurrent national average), 0 (not significantly different from the national average), or 1 (significantly worse than the national average). The values are totaled to create a healthy housing score for each community (-20 being best and 20 worst). The communities are ranked based on their scores. A score of 0 is considered average.

We classified the communities as follows:
Score of 8 or higher                        MOST UNHEALTHY
Score between 7 and -3                FAIR
Score of -4 or lower                        MOST HEALTHY

How did you decide which housing characteristics to analyze?
We selected housing characteristics from the U.S. Census Bureau’s American Housing Survey that either directly or indirectly impact health or safety. The characteristics are largely based on the federal “housing quality standards,” which set forth the requirements for decent, safe, and sanitary conditions in federally-owned or assisted housing. The AHS has been collecting information on these variables for over 30 years using a validated survey protocol. Based on expert opinion and in some cases, documented research, all of the characteristics selected can be expected to adversely affect the health of the residents.

Are some housing characteristics weighted more heavily than others in the analysis?
No. The 20 housing characteristics are given equal weight. We currently lack adequate information to demonstrate that any particular housing characteristic is more hazardous and deserves extra weighting.

What are the most common problems across the nation in 2011?
The most common problems were water leaks from the outside (11%) and inside (9%), signs of mice (10%). roofing problems (5%), damaged interior walls (5%), and foundation problems (5%)
What is NCHH doing about all this?
  • Research: NCHH conducts cutting-edge research to identify not only problems but also best practices and solutions. Please see to learn more about NCHH’s research.
  • Information and Materials: NCHH produces content and educational materials for consumers, professionals, and public decision makers. If after reviewing NCHH’s resources section you have additional questions, please visit “Ask NCHH” at
  • Training: Each year, the National Healthy Homes Training Center and Network trains thousands of housing, health, and other professionals on how to build and maintain healthier housing.
  • Policy/Advocacy: We are fighting for stronger legislation, regulations, and enforcement by Congress, federal and state agencies, and other key bodies. Please see for more information.
Why aren’t the data all from the same year?
Unlike the national American Housing Survey data that are published every two years, a consistent pattern of publication for the “Metro Edition” covering these 46 metro areas has declined in recent years. Previously, the Census Bureau’s website says the Metro surveys are supposed to be done every six years. However, the Bureau recently revised the plan to specify that Metro surveys will be done every four years. We expect that 2013 survey will include all metro areas not sampled in 2009 or 2011.

Wouldn’t jurisdictions with older data be unfairly penalized?
To ensure that locations were not penalized in the rankings for having older data, we compared each jurisdiction’s data to the most similar national year of data.

How was the survey conducted (e.g., number of people, site visits versus phone, repeat visits)?
The initial surveys are conducted through in-depth, face-to-face interviews with the homeowner or renter. Subsequent surveys are conducted by phone.

Why do many of the metrics have numerical rankings but don’t have “healthy” or “unhealthy” icons?

Only conditions that are significantly different statistically from the national average for a given survey year are noted with a green or red house icon.

How can my city make use of this data?

Municipal governments can use this data to engage in the following activities:
  • Use information to demonstrate need for healthy housing code enforcement
  • Present information to other agencies within government to start dialogue on healthy housing issues
  • Review strengths and areas for improvement with news outlets — demonstrate how the city has started to address housing problems or where they need more support
NGOs and community groups should use the State of Healthy Housing for the following activities:
  • Analyze data for strategic planning and areas to focus on
  • Present information to government agencies
  • Encourage more frequent, detailed data collection similar to this
  • Provide educational materials and resources to community members on housing hazard of concern

Learn More


State of Healthy Housing
Supporting Documentation