Where a Single-Income Home is Officially Impossible

The National Picture

Of the 25,811 zip codes with sufficient data, only 23% meet the conventional 3x affordability threshold. The national median ratio is 3.9x - meaning the typical American zip code is already in "moderately unaffordable" territory before accounting for down payment requirements, property taxes, insurance, or interest rates.

27% of zip codes - more than 6,900 - are severely unaffordable at 5x or above. 410 zip codes across the country exceed 12x, a level at which homeownership on a single median income is mathematically unreachable without external wealth.

The data shows that affordability today is not a feature of the sunbelt or the midwest as broad categories but it is increasingly a feature of places that have not yet attracted outside capital, or places where economic decline has suppressed demand.

The Most Unaffordable Markets

The single most unaffordable zip code in the country is Sagaponack, NY (11962) in the Hamptons, at a ratio of 71.5x. The typical home value there is $6.4 million against a median household income of $89,886 indicating these ultra-luxury coastal communities' home values have detached entirely from local income.

The most unaffordable major metro is Santa Barbara, CA at a median ratio of 12.9x across its zip codes, followed by Los Angeles at 10.7x and Maui (Kahului-Wailuku-Lahaina) at 10.4x. In the Los Angeles metro alone, 30% of zip codes exceed 12x.

Two Types of Impossible

One of the most important things this map reveals is that extreme unaffordability has two very different causes.

In luxury markets - Aspen (37x), Wilson WY near Jackson Hole (36x), Rancho Santa Fe (38x), Beverly Hills (27x) - home prices are astronomical and have decoupled from local incomes. These are resort, second-home, and ultra-wealthy enclave markets where the median buyer is not a median-income household.

In poverty markets - the South Bronx (10454) at 29.6x, parts of Stockton CA at 13.9x, downtown New Orleans at 13.7x - home values are not exceptional, but incomes are so low that even modest homes are unreachable. A home worth $330,000 is "affordable" by national standards but represents 14 years of income for a household earning $23,000.

The States

Hawaii is the most unaffordable state by a wide margin. 96% of Hawaiian zip codes exceed the 5x severe threshold, and 64% exceed 8x. This reflects a combination of constrained land supply on islands, high construction costs, strong tourism and second-home demand, and relatively modest local incomes outside of Honolulu.

California is second at 88% of zip codes above 5x. What's striking about California is the breadth - unaffordability is not confined to the Bay Area and Los Angeles. It extends into the Central Valley, the Inland Empire, and rural coastal counties.

The surprise entries are Montana (68% above 5x) and Idaho (81% above 5x). These states have seen dramatic in-migration from higher-cost metros, particularly during and after 2020, driving home values up sharply while local wages remained largely flat. The "move somewhere affordable" migration has itself made the destination unaffordable.

The most affordable states are Illinois (median 2.6x), West Virginia (2.7x), and Kansas (2.7x). Illinois' number is pulled down by the large number of affordable downstate zip codes offsetting the Chicago metro. West Virginia's affordability is better but context-dependent - low ratios there often reflect low home values in economically depressed areas, not necessarily strong local prosperity.

The Inland Surprises

Not all extreme unaffordability is coastal. The data surfaces a distinct pattern of inland resort and vacation markets where home values have been driven by second-home and investment demand far beyond what local incomes can support.

Bozeman, MT registers a metro median of 10.2x. Cashiers, NC (a mountain resort town in western North Carolina) comes in at 20x. Sullivans Island, SC near Charleston reaches 23.6x. Glenwood Springs, CO has 42% of its zip codes in the "effectively impossible" tier.

The Affordable Places

Genuine affordability still exists. Rural Kentucky, West Virginia, and Ohio have zip codes where the ratio falls below 1x - meaning a typical home costs less than one year of median household income. Small metros like Johnstown, PA (median 1.6x), Fairmont, WV (1.7x), and Decatur, IL (1.9x) remain accessible by any reasonable standard.

What ZHVI measures and what it doesn't

The Zillow Home Value Index is not median sale price. It estimates the value of the middle tier (35th–65th percentile) of homes in a given area using Zillow's Zestimate model, smoothed and seasonally adjusted. This makes it more stable than transaction-based medians (which can be skewed by month-to-month changes in sales mix) and provides coverage in markets too thin for a reliable transaction average.

The practical effect is that ZHVI tends to be slightly conservative relative to actual market peaks meaning the affordability picture shown here may be slightly better than what buyers actually face in a hot market. The true situation is likely at least as bad as the map shows.

Household income vs. single income

The Census ACS B19013 table measures median household income - the income of the entire household, which may include multiple earners. The "single income" framing in this project's title refers to whether a typical household, earning the local median, can afford a typical home. It does not assume a single-earner household.

The 3x, 5x, and 8x thresholds used here are standards applied to household income by lenders and housing economists. A ratio above 8x means the household, however many earners it has, cannot afford the home by conventional standards.

The Census $250,001 income cap

The ACS top-codes median household income at $250,001. Any ZCTA where the true median exceeds this reports $250,001. This affects very high-income zip codes. For example, Atherton, CA (94027), which registers at 32.3x using the $250,001 cap. The true median income in Atherton is likely above $400,000, which would bring the ratio to approximately 20x - still extreme, but the cap makes it appear worse than reality. The map is therefore slightly conservative in its depiction of luxury markets.

What the ratio doesn't capture

The price-to-income ratio is a simplified metric. It does not account for:

• Down payment requirements - a 20% down payment on a $600,000 home requires $120,000 in cash before any mortgage is involved
• Interest rates - at 7% mortgage rates, monthly payments are significantly higher than at 3%, compressing affordability further
• Property taxes, insurance, and maintenance - the total cost of homeownership significantly exceeds the mortgage payment alone
• Wealth and equity - many buyers bring equity from a prior home sale, making the income ratio less relevant to their actual purchasing power
• Rental markets - unaffordability to buy does not directly translate to unaffordability to rent, though the two are correlated

The ratio is best understood as a signal, not a complete affordability assessment. A 10x ratio does not mean every household in that zip code cannot buy a home - it means the median household cannot do so by conventional lending standards without additional resources.

Coverage gaps and excluded zip codes

Not every zip code appears on the map. Areas are excluded when:

• No Zillow coverage - Zillow requires a minimum number of homes to produce a stable index. Rural and very sparse zip codes are excluded from the ZHVI dataset. This does not mean those areas are affordable, it means there are too few home sales for a reliable estimate.
• Suppressed Census income data - the ACS suppresses income estimates for ZCTAs with too few survey respondents, returning a value that is excluded from this analysis.
• Below income threshold - zip codes with ACS median income below $15,000 were excluded as statistically unreliable. These represent approximately 61 ZCTAs nationally.
• ZCTA vs. zip code mismatch - ZCTAs are the Census Bureau's polygon approximation of USPS zip codes. Some USPS zip codes (PO Boxes, military APO/FPO codes) have no ZCTA equivalent and cannot appear on the map.

What the shapes mean

ZCTA boundaries follow street centerlines, railroad tracks, waterways, and administrative boundaries as defined by the Census Bureau. They were designed for statistical data collection, not cartographic clarity. In dense urban areas, ZCTAs can be small and irregular. In rural areas, a single ZCTA may cover hundreds of square miles. The shape of the polygon on the map does not reflect population density. A large orange polygon in the Great Plains may represent fewer people than a tiny dark polygon in Manhattan.