2 Housing Markets and Affordability

How housing markets work

Housing markets connect households seeking homes with owners, builders, and landlords offering them. A home is both a place to live and a costly, long-lived asset. Because homes differ by location, size, condition, and access to jobs and services, housing is made up of many related local markets rather than one uniform market.

Supply, demand, and land use

Housing demand is the number and kinds of homes people are willing and able to rent or buy at different prices. It changes with population, household formation, employment, income, preferences, and access to financing. Demand is not the same as need: households with the greatest need may have too little income or credit to compete in the private market.

Housing supply includes the stock of homes available as well as new construction and conversions. In the short run, supply is relatively fixed because new homes take time to plan, finance, permit, and build. When demand rises faster than the number of available homes, rents and prices tend to increase. Over time, construction can add supply, but the response varies with building costs, land availability, infrastructure, and expected returns.

Land-use rules shape which homes can be built and where. Zoning may limit building height or density, require large lots or parking, or prohibit apartments in some areas. Such rules can constrain the number and variety of homes, particularly in places with high demand. Allowing more homes can support added supply, but zoning changes alone do not guarantee homes affordable to households with low incomes; subsidies and dedicated affordable housing may also be needed. Research finds that effects vary by policy and local market.

Measuring housing affordability

A household’s ability to afford housing depends on the price of a home and the household’s resources. Higher income generally makes a given rent or mortgage easier to pay. But when housing costs rise faster than income, households may have fewer choices or less money for food, transportation, health care, and other needs.

A simple affordability check compares monthly housing costs with monthly household income:

HUD commonly classifies households spending more than $30\%$ of their income on housing as cost-burdened; spending more than $50\%$ is severe cost burden. These measures are useful screening indicators, not complete tests of affordability. They do not show how much income remains for other necessities or fully account for differences in household size and local costs. Housing costs may include rent and utilities, or, for owners, mortgage payments, taxes, insurance, and other costs.

For example, a household with monthly income of $\$4{,}000$ that spends $\$1{,}500$ on housing uses $37.5\%$ of its income for housing and is cost-burdened under the $30\%$ measure. A household with the same housing bill but monthly income of $\$6{,}000$ spends $25\%$ and is not cost-burdened by that measure.

Credit and the full cost of housing

Credit affects both access to housing and its cost. Mortgage lenders consider credit history, existing debt, savings, income, and other factors when deciding whether to lend and what interest rate to offer. A higher interest rate raises the monthly payment for the same loan and reduces the home price a buyer can afford. Credit history can also affect renters’ access to housing or the deposit a landlord requests. As a result, a household may face unaffordable housing even when homes are available if it cannot qualify for financing or meet upfront costs.

The full cost of owning extends beyond the mortgage payment: property taxes, insurance, utilities, maintenance, and repairs matter too. For renters, rent, utilities, deposits, and moving costs affect the budget. A lender’s approval amount is not necessarily a comfortable household budget; affordability also depends on debts, savings, and other essential expenses.

Segregation and housing insecurity

When homes in well-resourced areas are scarce or expensive, lower-income households may be excluded from neighborhoods with good access to jobs, schools, transit, and services. Land-use restrictions can contribute to this pattern, while past and present discrimination and unequal access to credit also shape who can live where. These forces can reinforce racial and economic segregation.

Affordability is not only a matter of the total number of homes. Location, housing type, household income, and access to assistance also matter. When housing costs consume a large share of income, households have less protection against job loss, rent increases, or emergencies. Severe cost burden can increase the risk of eviction and homelessness, though homelessness has multiple causes and cannot be explained by housing supply alone.

Different responses can address different parts of these problems. Expanding housing choices, preserving or building subsidized homes, and providing rental assistance are distinct tools. Increasing the number of homes can support added supply, while targeted assistance may still be needed to make housing affordable to households with low incomes.