Common Words

Housing can be complex, and so can its vocabulary.

From ADUs and missing middle to housing choice voucher and LIHTC, we’ve got a robust list of words and acronyms that are commonly used to describe housing needs and housing solutions – and what they mean. Not seeing what you’re looking for? Email us at


Housing Definitions

Area median income, or AMI

The midpoint of a region’s income distribution – half of households earn more than the median and half earn less than the median. It’s used to calculate income limits for eligibility in a variety of housing programs.

Available rental housing

Any rental unit currently available for rent.

Basic rent

The minimum monthly rent that tenants who do not have rental assistance pay to lease units developed through certain housing programs. It’s calculated as the amount of rent required to operate the property, maintain debt service on a subsidized mortgage with a below-market interest rate and provide a return on equity to the developer in accordance with the regulatory documents governing the property.

Contract rent

The actual monthly rent payable by the tenant, including any rent subsidy paid on behalf of the tenant to the owner, inclusive of all terms of the lease or the monthly rent agreed to between a tenant and a landlord.

Cost-overburdened household

A household that pays more than 30% of its annual income on housing. This includes mortgage, rent, taxes, insurance, etc.

Elderly person

An individual who is at least 62 years old as defined by the U.S. Department of Housing and Urban Development, or HUD.

Elderly or senior housing

Housing where all the units on the property are restricted for residents who are 62 or older, or at least 80% of the units in each building are restricted for households where at least one member is 55 or older and the housing is designed with amenities and facilities designed to meet the needs of older residents.

Extremely low-income

A person or household with income below 30% of AMI adjusted for household size.

Fair market rent, or FMR

The estimates established by HUD of the gross rents – contract rent plus tenant-paid utilities – needed to obtain modest rental units in acceptable condition in a specific county or metropolitan statistical area. HUD generally sets FMR so 40% of the rental units have rents below the FMR. In rental markets with a shortage of lower-priced rental units, HUD may approve the use of FMRs that are as high as the 50th percentile of rents.

Frail elderly

A person who is at least 62 years old and is unable to perform at least three “activities of daily living” comprising of eating, bathing, grooming, dressing or home management activities as defined by HUD.

Garden apartment

An apartment in a low-rise building – typically two to four stories – that features low density, ample open space around buildings and on-site parking.

Gross rent

The monthly housing cost to a tenant that equals the contract rent provided for in the lease plus the estimated cost of all tenant-paid utilities.


One or more people who live in a housing unit as their usual place of residence.

Housing choice voucher, or Section 8 program

A federal rent subsidy program under Section 8 of the U.S. Housing Act that issues rent vouchers to eligible households to use in the housing of their choice. The voucher payment subsidizes the difference between the gross rent and the tenant’s contribution of 30% of adjusted gross income, or 10% of gross income, whichever is greater. In cases where 30% of the tenant’s income is less than the utility allowance, the tenant receives an assistance payment. In other cases, the tenant is responsible for paying their share of the rent each month.

Housing gap

The total demand from eligible households who live in certain housing conditions less the available or planned housing stock.

Housing unit

A house, apartment, mobile home or group of rooms used as a separate living quarter by a single household.

HUD Section 202 program

A federal program that provides direct capital assistance, such as a grant, and operating or rental assistance to finance housing designed for occupancy by elderly households who have income not exceeding 50% of AMI. The program is limited to housing owned by 501(c)(3) nonprofit organizations or by limited partnerships where the sole general partner is a 501(c)(3) nonprofit organization. Units receive HUD project-based rental assistance that enables tenants to occupy units at rents based on 30% of tenant income.

HUD Section 236 program

A federal program that provides interest-reduction payments for loans that finance housing for households with income not exceeding 80% of AMI who pay rent equal to the greater of basic rent or 30% of their adjusted income. All rents are capped at a HUD-approved market rent.

HUD Section 811 program

A federal program that provides direct capital assistance and operating or rental assistance to finance housing designed for occupancy by individuals with disabilities who have income not exceeding 50% of AMI. The program is limited to housing owned by 501(c)(3) nonprofit organizations or by limited partnerships where the sole general partner is a 501(c)(3) nonprofit organization.

Income limits

The maximum household income by county or metropolitan statistical area adjusted for household size and expressed as a percentage of the AMI for the purpose of establishing an upper limit for eligibility for a specific housing program. Income limits for federal, state and local rental housing programs typically are established at 30%, 50% 60% or 80% of AMI.

Low-income household

A person or household with gross household income between 50% and 80% of AMI adjusted for household size.

Low-income housing tax credit, or LIHTC

A federal program that supports the acquisition, construction and rehabilitation of affordable rental housing for households with low to moderate incomes. Many types of rental housing are eligible for the LIHTC, including apartment buildings, single-family homes, townhouses and duplexes. The program requires a certain percentage of units built be restricted for occupancy to households earning 80% or less of AMI, and rents on these units be restricted accordingly.

Market vacancy rate

The average number of apartment units in any market that are unoccupied divided by the total number of apartment units in the same market, excluding units in properties that are in the lease-up stage.

Mixed-income property

An apartment property that has both income-restricted and unrestricted units or units restricted at two or more income limits. For example, a low-income tax credit property with income limits of 30%, 50% and 60%.

Moderate income

A person or household with gross household income between 40% and 60% of AMI adjusted for household size.

Non-conventional rentals

Structures that generally have four or fewer rental units.

Overcrowded housing

Housing units with 1.01 or more persons per room. These units often are home to multi-generational families or large families who need appropriately sized and affordable housing units.

Pipeline housing

Housing that is under construction or is planned or proposed for development.

Population trends

Changes in population levels for a particular area over a specific period of time that is a function of the level of births, deaths and net migration.

Project-based rent assistance

Rental assistance from any source that is allocated to the property or a specific number of units in the property and is available to each income-eligible tenant of the property or an assisted unit.

Conventional public housing or low-income conventional public housing

A HUD program administered by local or regional housing authorities that serves low- and very low-income households with rent based on the same formula used for HUD Section 8 assistance.

Rent burden

Gross rent divided by adjusted monthly household income.

Rent-burdened households

Households with rent burden above the level determined by the lender, investor or public program to be an acceptable rent-to-income ratio.

Restricted rent

The rent charged under the restrictions of a specific housing program or subsidy.

Single-family housing

A dwelling unit – attached or detached – designed for use by one household and with direct access to a street. It does not share heating facilities or other essential building facilities with any other dwelling.

Special needs population

A specific market niche that is typically not catered to in a conventional apartment property. Examples of special needs populations include individuals who have substance abuse, are visually impaired or who have mobility limitations.

Standard condition

A housing unit that meets HUD’s Section 8 housing quality standards.

Subsidized housing

Housing that operates with a government subsidy often requiring tenants to pay up to 30% of their adjusted gross income toward rent and often limiting eligibility to households with incomes of up to 50% or 80% of AMI.


A monthly income received by a tenant or by an owner on behalf of a tenant to pay the difference between the apartment’s contract rent and the amount paid by the tenant toward rent.

Substandard housing

Housing that lacks complete indoor plumbing facilities and often considered to be of such poor quality and in disrepair that it should be replaced.

Substandard conditions

Housing conditions that are conventionally considered unacceptable, which may be defined in terms of lacking plumbing facilities, one or more major systems not functioning properly or overcrowded conditions.


An individual who rents real property from another.

Tenant-paid utilities

The cost of utilities necessary for living in a dwelling unit that are paid by the tenant. This does not include cable, phone or internet.


The distinction between owner-occupied and renter-occupied housing units.

Townhouse, or row house

A single-family attached residence separated from another by party walls, usually on a narrow lot offering a small front and back yard.

Vacancy rate

The number of total habitable units that are vacant divided by the total number of units in the property.

Very low-income household

A person or household with gross household income between 30% and 50% of AMI adjusted for household size.

Windshield survey

An on-site observation of a physical property or area that considers only the perspective viewed from the windshield of a vehicle. Such a survey does not include interior inspections or evaluations of physical structures.