Every conversation about housing affordability eventually arrives at a number that is large enough to feel abstract but concrete enough to explain nearly everything else: 4 million. That is approximately how many homes the United States is short of meeting the housing needs of its population right now. Not 4 million luxury units. Not 4 million vacation properties. Four million homes that should exist, starter homes, rental units, townhouses, apartments, and simply don’t, because for more than a decade, the country has built far less housing than the number of households being formed.
That shortfall is not a statistic sitting in a single report. It is the denominator of the entire affordability crisis. It is why home prices have surged 50% since 2020. It is why rental costs have climbed fast enough to make saving for a down payment nearly impossible for middle income earners. It is why first time buyers are competing in the same market against investors, move up buyers, and cash purchasers with existing equity to deploy, and consistently losing. Understanding the supply gap does not require a degree in economics. It requires understanding one simple principle: when there are significantly more buyers than available homes, prices go up, and they stay up until supply catches up.
Supply has not caught up. It is falling further behind.
A decade of underbuilding coming due
The housing shortage in the United States continued to widen in 2025, with the national supply gap reaching an estimated 4.03 million homes according to Realtor.com’s 2026 Housing Supply Gap Report. In 2025, approximately 1.41 million new households were formed across the country while only 1.36 million housing starts were recorded, an annual shortfall of about 50,000 homes that, while modest on its own, compounds a cumulative deficit built over more than a decade of underbuilding.
The South carries the largest regional deficit at approximately 1.62 million homes, followed by the Northeast at 952,000, the Midwest at 865,000, and the West at 660,000. Measured against total construction since 2012, the Northeast faces the most acute gap even after modest improvement in recent starts. These are not regions where housing was expected to be unaffordable. Several of these markets, particularly in the Midwest and South, were long considered the country’s affordable alternatives to expensive coastal cities. The shortage has found them too, and the people who moved there hoping to escape unaffordable markets have discovered that the problem followed them.
Even when annual construction and household formation are roughly balanced, the market is still digging out from more than a decade of underbuilding, as Realtor.com’s chief economist Danielle Hale noted. The fact that it would take roughly seven years to eliminate the deficit even under an optimistic building scenario highlights just how significant and persistent this shortage has become. Seven years is not a near term fix. It is a generational timeline for a problem that is affecting buyers right now, today, who cannot wait seven years for the market to rebalance.
Why builders aren’t building faster
The instinctive response to a shortage is to build more, and builders have tried. Housing completions in 2025 remained historically elevated. Single family and multifamily starts have been running at levels not seen since before the Great Recession in some years. The problem is not that the industry has been idle. The problem is that the structural obstacles to construction are so numerous, so entrenched, and so resistant to quick resolution that even elevated building rates have not been enough to close a gap this large.
Zoning is where the analysis typically begins, and for good reason. Single family zoning, which restricts large swaths of residential land in most American cities and suburbs to detached single family homes only, remains one of the most significant regulatory barriers to increasing housing density. Local zoning boards influenced by NIMBYism have historically blocked or delayed higher density development, from duplexes and accessory dwelling units to apartment buildings near transit corridors. The result is a landscape in which land is technically available for housing but legally restricted from being used for the types of housing that the market actually needs most, smaller, denser, and more affordable units.
At the local level, there remain too many review cycles in permitting, and limited consistency from town to town with local inspectors. One developer reported he couldn’t get a certificate of occupancy for two months because the town requested he change the property’s address. In Colorado alone, there are over 300 different building codes. This fragmentation of regulatory authority is not a minor inconvenience. It adds time, cost, and uncertainty to every development project, and at the margins, it is enough to tip projects that might have proceeded into abandonment.
Labor is another constraint that has worsened. The construction industry has faced workforce challenges since the Great Recession, when approximately one million workers left the sector and did not return. Immigrants make up about 30% of the construction labor force, and the ongoing immigration crackdown is expected to reduce that supply further going forward. High interest rates have compounded the problem, with loan rates for smaller builders rising sharply. Regulatory costs now add an estimated $94,000 per home, about one quarter of the total price, underscoring the need for deregulation to improve affordability.
The cost of building materials has risen 41.6% since the COVID 19 pandemic, far outpacing overall inflation. Recent tariff actions alone are estimated to add an average of $10,900 to the cost of constructing a new single family home. As builders shift toward constructing higher priced homes to cover their expenses, the entry level housing that first time homebuyers rely on is disappearing from new construction pipelines. This last point is particularly important. Even when builders are building, the economics of construction push them toward larger, more expensive homes where margins are easier to achieve. The starter home, the traditional entry point into homeownership for first time buyers, has become increasingly rare in new construction, precisely because it is the hardest type of home to build profitably under current cost conditions.
The construction industry faces a labor gap of nearly 500,000 workers heading into 2026. An AGC NCCER survey found that 43% of general contractors reported at least one project canceled, postponed, or scaled back in the past six months due to higher material costs driven by tariffs. These numbers, labor gaps and project cancellations, do not appear in housing affordability reports. They appear in construction industry filings. But they are direct causes of the supply gap, and their downstream effect is felt by every buyer competing for a home in a market where supply is structurally constrained.
The NIMBYism problem
NIMBYism, the political mobilization of existing residents to block new housing development in their neighborhoods, is not new, but its consequences have never been more visible than they are right now. The core dynamic is straightforward: people who own homes have a financial interest in constraining supply, because more supply puts downward pressure on home values. Existing homeowners show up at zoning meetings. They organize. They sue. They elect local officials who share their preferences. First time buyers and renters, the people most harmed by housing restrictions, are geographically diffuse, politically less organized, and often not yet living in the communities where the decisions are being made.
NIMBYism manifests in local meetings dominated by older residents opposed to change. Even fast growing Sunbelt regions like Texas and Florida have curtailed building, mirroring the coastal NIMBYism long associated with cities like San Francisco and New York. Research highlights how concentrated development sparks backlash over traffic, schools, and neighborhood character, further entrenching opposition. Politicians face genuine dilemmas, as serving the immediate concerns of vocal local constituents often clashes with the broader regional interest in housing production.
The legal system has increasingly become a tool for blocking reform. Courts in Montana enjoined two state laws allowing duplexes and accessory dwelling units in single family neighborhoods, ruling that the laws violated equal protection guarantees. In Los Angeles County, a judge blocked a California state law allowing duplexes to be built in single family zones from going into effect in five Southern California cities, ruling it an irrational means of furthering the state’s interest in affordable housing because it didn’t require that newly legal duplexes be rented or sold at below market rates. These rulings illustrate a pattern: state legislatures pass zoning reform in response to documented housing crises, and local opponents use litigation to delay or nullify those reforms, often for years.
Where reform is actually happening
The picture is not entirely bleak. There is meaningful reform activity across the country, and some of it is producing real results, though the scale of what’s working remains far smaller than the scale of what needs to change.
California’s accessory dwelling unit reforms are the most cited example of what supply side policy can accomplish at scale. Before California first relaxed ADU restrictions in 2016, fewer than 1,000 ADUs were permitted annually statewide. By 2021, that number had risen to over 20,000 annually, a more than 20 fold increase driven by reforms that reduced parking requirements, streamlined permitting, and reduced the ability of localities to add obstructive conditions to ADU approvals. The progress was not linear, as localities found workarounds, additional legislative fixes were needed in 2017, 2019, 2021, and 2022, but the cumulative effect has been a meaningful increase in housing supply in a state that has been short for decades.
YIMBY backed reforms passed in 13 states in the most recent legislative cycle, easing zoning for accessory dwelling units, reducing parking mandates, and blocking building moratoriums. Maryland now requires counties to permit backyard units. Florida curtailed local bans on apartments. Arizona adjusted construction start times to aid developers. Montana’s reforms went further still, effectively eliminating single family only zoning in cities with populations over 5,000, though those reforms are still being contested in court. California’s Senate Bill 79, passed in 2025, upzones areas around transit stops in key counties, extending the logic of ADU reform to larger scale density increases near public transportation.
At the federal level, the Housing Supply Frameworks Act, a bipartisan bill introduced in the House, would create a national strategy for boosting housing production by providing communities with technical assistance and best practices for reducing regulatory barriers. Realtor.com’s Let America Build campaign, launched in March 2025, has called on lawmakers to cut through restrictive zoning and outdated regulations, lobby for modernized zoning, overcome NIMBYism, and advocate for what advocates call the “missing middle”, the duplexes, triplexes, townhouses, and small apartment buildings that fall between single family homes and large multifamily developments and are currently illegal to build in most American residential neighborhoods.
Why fixing supply is not enough on its own
It is worth being precise about what closing the supply gap would and would not accomplish. More housing supply would, over time, moderate price growth and eventually reduce prices in the most supply constrained markets. It would create more options for first time buyers and renters. It would reduce the competitive intensity that currently makes homebuying so grueling. These are meaningful outcomes, and they are the right goals to pursue.
But supply alone cannot solve the affordability crisis for the households currently most locked out of homeownership, lower income buyers, first generation buyers, buyers of color navigating discriminatory lending and appraisal systems, and households carrying student debt that constrains their mortgage qualification regardless of how many homes are available. For those households, supply side reform is necessary but not sufficient. Because the housing supply gap report’s headship measure captures both renters and owners, it argues that more affordable rental stock has to be part of the fix, not just ownership inventory. A market with more homes is a better market. But a market with more homes, better lending practices, stronger anti discrimination enforcement, and properly resourced assistance programs is the market that can actually move the numbers that matter most.
The supply crisis is the foundation of the housing affordability problem. Every other challenge, from high prices to racial homeownership gaps to the declining rate of first time buyers, is built on the same base: there are not enough homes. That foundation has been crumbling for more than a decade. Fixing it will take more time, more political will, and more sustained effort than any single administration, any single bill, or any single reform wave has yet produced. But it is where the work has to begin, and in 2026, after years of treating housing supply as a local issue, there are finally signs that national policymakers are starting to take that seriously.
References
Business Report. (2025, November 5). Labor shortages and tariffs are squeezing homebuilders as costs climb. https://www.businessreport.com/business/labor-shortages-and-tariffs-are-squeezing-homebuilders-as-costs-climb
Construction Owners Association of America. (2026, March 8). US housing supply gap surpasses 4 million homes as construction trails demand. https://www.constructionowners.com/news/us-housing-shortage-tops-4-million-homes
Everyday States. (2026, February 24). YIMBY’s tough road ahead: Can pro housing reforms survive homeowner pushback? https://everyday-states.com/yimbys-tough-road-ahead-can-pro-housing-reforms-survive-homeowner-pushback/
HousingWire. (2025, March 20). How the US can fix its housing supply crisis. https://www.housingwire.com/articles/build-baby-build-how-the-us-can-start-fixing-its-housing-supply-crisis/
HousingWire. (2026, February 12). Commodity price volatility hits homebuilders as tariffs reshape costs. https://www.housingwire.com/articles/builder-material-costs-tariffs/
NAHREP. (2025, October 21). Building barriers: How rising construction costs impact the housing affordability crisis. https://nahrep.org/housinghub/2025/10/21/building-barriers-how-rising-construction-costs-impact-the-housing-affordability-crisis/
National Housing Crisis Task Force. (2025, October 27). Land use, permitting, & building code reform: A path forward. https://nationalhousingcrisis.org/toolkit/regulation-policy/land-use-permitting-building-code-reform-a-path-forward/