Rainstone Water Heaters research program · Data: U.S. Census Bureau, American Community Survey (ACS) 2024 5-year estimates, pulled October 22, 2026 · Universe: Texas places with 10,000 or more housing units
The short version
We analyzed U.S. Census Bureau data on when Texas homes were built — every incorporated place in the state with at least 10,000 housing units — and ranked them two ways: the share of homes built in 1939 or earlier, and the median year built (the midpoint: half a place’s homes are older, half newer).
Fort Worth has the oldest housing stock of any big city in Texas. About 1 in every 18 Fort Worth homes was standing before 1940. Dallas’s typical home is the oldest of any large Texas city — built in 1981. And in the San Antonio metro, the oldest stock belongs to San Antonio itself, with more than 31,000 pre-1940 homes.
Why does a water heater company publish this? Because a home’s age is the single best predictor of what’s happening inside its walls. Pre-1940 homes were plumbed in another era — and that story is told, carefully and without a sales pitch, further down this page.
Key findings
- Fort Worth is #1 among Texas’s five largest cities: 5.59% of its homes — 20,898 of 373,948 — were built in 1939 or earlier, ahead of Dallas (5.09%) and San Antonio (5.08%).
- Dallas has the oldest median year built of any Texas place with 250,000+ people: 1981. Half of Dallas’s homes predate 1981. Houston and Corpus Christi follow at 1982, El Paso and Lubbock at 1984, and San Antonio at 1985.
- San Antonio leads its metro: 5.08% pre-1940 (31,158 homes) — #1 of the 8 San Antonio-metro places at this study’s size floor, ahead of Seguin and New Braunfels.
- Two smaller DFW cities edge out every big city: Waxahachie (6.48% pre-1940) and Greenville (5.83%) hold the DFW metro’s top two spots; Fort Worth is #3 in its own metro while being #1 among the big cities.
- The same #1 holds in Fort Worth’s size class: among Texas places with 500,000–1,000,000 people, Fort Worth (5.59%) leads El Paso (4.66%) and Austin (2.24%).
The big-city table — Texas’s five largest cities, ranked
How to read this table: ranked by the share of housing units built in 1939 or earlier (Census ACS table B25034), among Texas’s five largest cities by population. Counts are published next to shares — a percentage on a small base and the same percentage on a large one are different stories.
| Rank | City | Homes built 1939 or earlier (share) | Pre-1940 homes (count) | Total housing units |
|---|---|---|---|---|
| 1 | Fort Worth | 5.59% | 20,898 | 373,948 |
| 2 | Dallas | 5.09% | 30,041 | — |
| 3 | San Antonio | 5.08% | 31,158 | 612,901 |
| 4 | Houston | 3.97% | — | — |
| 5 | Austin | 2.24% | — | — |
The rankings published in this study — every figure shown on this page, exactly as verified — are published with this study as a downloadable CSV.
Read Dallas and San Antonio as effectively tied for second: they are separated by a single hundredth of a percentage point, well inside the survey’s margin of error. The estimates and their margins of error are in the downloadable data, and the ordering above is simply the published estimates as computed. Fort Worth’s lead, on roughly 374,000 homes, is the finding.
One count deserves a second look: San Antonio’s 31,158 pre-1940 homes are the largest raw count in this table — more century-old homes than Dallas or Fort Worth hold, spread across a much larger housing stock. Old neighborhoods are a bigger absolute presence in San Antonio even where the share runs a hair behind.
Size-class table — places with 500,000–1,000,000 people
| Class rank | City | Homes built 1939 or earlier (share) |
|---|---|---|
| 1 | Fort Worth | 5.59% |
| 2 | El Paso | 4.66% |
| 3 | Austin | 2.24% |
Fort Worth’s win isn’t an artifact of the big-city framing — it leads its natural population class outright, by nearly a full percentage point over the runner-up.
Oldest median year built — Texas places with 250,000+ people
The median year built (ACS table B25035) answers a different question: not how many very old homes a city has, but how old its typical home is.
| Rank | City | Median year built |
|---|---|---|
| 1 | Dallas | 1981 |
| 2 (tie) | Houston | 1982 |
| 2 (tie) | Corpus Christi | 1982 |
| 4 (tie) | El Paso | 1984 |
| 4 (tie) | Lubbock | 1984 |
| 6 | San Antonio | 1985 |
Correction — October 30, 2026: the ranking in this table was corrected after a full-dataset validation. San Antonio’s median year built (1985) was right as published; its rank is 6th, not 4th — El Paso and Lubbock, each with a median year built of 1984, tie at 4th and were missing from the original table. The study’s downloadable CSV has been updated to the full validated dataset.
Dallas takes this field outright: the typical Dallas home was built in 1981, which makes it more than four decades old — and half the city’s homes are older still. (Median years for the remaining 250,000+ places in the pulled data ship in the downloadable CSV; the six above are the oldest medians in the field.)
Metro editions
Dallas–Fort Worth metro (places with 10,000+ housing units)
| Metro rank | City | Homes built 1939 or earlier (share) |
|---|---|---|
| 1 | Waxahachie | 6.48% |
| 2 | Greenville | 5.83% |
| 3 | Fort Worth | 5.59% |
Roughly 1 in 15 Waxahachie homes predates 1940 — the oldest stock in the metroplex. Fort Worth’s #3 here is the honest context for its big-city #1: the metro’s very oldest housing sits in its smaller historic cities, and Fort Worth leads where cities of its size compete.
San Antonio metro (8 places with 10,000+ housing units)
| Metro rank | City | Homes built 1939 or earlier (share) | Pre-1940 homes (count) | Total housing units |
|---|---|---|---|---|
| 1 | San Antonio | 5.08% | 31,158 | 612,901 |
| 2 | Seguin | 4.46% | — | — |
| 3 | New Braunfels | 3.07% | 1,367 | 44,517 |
New Braunfels’ 1,367 pre-1940 homes — about 1 in every 33 houses in the city — reflect its German-Texan building stock, among the most distinctive historic housing in Central Texas.
What old housing stock means for your plumbing
A city’s water system gets graded on the EPA’s record. A home’s plumbing gets graded by time — and homes built before 1940 were plumbed for a different era:
- Galvanized lines. Pre-war homes were typically piped in galvanized steel, which corrodes from the inside out over the decades — narrowing the pipe, dropping water pressure, and sometimes tinting the water. Any original galvanized line still in service today has been working far beyond the span it was installed for.
- Cast-iron drains. The drain side of a pre-1940 home is usually cast iron, which scales, cracks, and bellies with age. It fails slowly, then all at once.
- Patchwork generations. Almost no pre-war home is on fully original plumbing. Most have been re-piped in sections across 80-plus years — a copper run here, a replacement there — which means the system’s real condition varies room by room, and nobody knows its state until someone looks.
- The water heater lineage. A 1930s home has hosted many generations of water heaters. What’s in the closet or attic now matters more than what was there first — its age, its sediment load, and whether its connections were updated when it went in.
None of this is an argument against old homes — they’re the most characterful housing stock Texas has, and their owners know it. It’s an argument for knowing what you’re running. If you’re in one of our Texas service areas and want a straightforward read on an older home’s water heater and lines, that’s the work Rainstone Water Heaters does every day — no pressure, and this study stands on its own whether or not you ever call us.
Ranked city? Get your badge
If your city appears at the top of one of these tables, you’re welcome to post the result wherever your city posts honors like this — your news page, historic-preservation page, or awards page. We provide a ready badge (PNG and SVG, with a copy-paste embed), a one-page PDF summary of the study, the video at the top of this page as an embed, and a suggested social post. There’s no cost and no obligation, and the ranking stands whether or not you post anything. Contact the research team at [email protected].
Methodology in brief
Full methodology: published in full below. In short: U.S. Census Bureau American Community Survey 2024 5-year estimates, tables B25034 (Year Structure Built) and B25035 (Median Year Structure Built), pulled October 22, 2026; all 1,862 Texas places pulled, ranked fields limited to places with 10,000 or more housing units so percentages are stable; “pre-1940” = the ACS “1939 or earlier” category; metro fields use Census CBSA definitions. One caveat we print rather than bury: the ACS is a survey, so every figure is an estimate with a margin of error — published in the downloadable data. Where two cities are separated by less than the margin of error (Dallas and San Antonio in the big-city table), we say so on the page rather than pretending a hundredth of a point is a verdict.
FAQ
Where does this data come from? The U.S. Census Bureau’s American Community Survey, 2024 5-year estimates — tables B25034 (Year Structure Built) and B25035 (Median Year Structure Built), for Census places. Every figure on this page can be checked against the published ACS tables.
Why “built in 1939 or earlier”? It’s the Census Bureau’s own oldest category in B25034, and it’s the meaningful line for housing stock: homes built before 1940 were framed, wired, and plumbed before modern residential codes and materials. We use the Bureau’s category as-is rather than inventing a cutoff.
What’s the difference between the share ranking and the median year? The share counts a city’s very old homes. The median describes its typical home. A city can have a modest pre-1940 share but an old typical home — Dallas is the example: #2 on share among the big five, and #1 outright on median year built.
Does an old home mean bad plumbing? No. It means plumbing from another era, usually replaced in sections over the decades. The study measures the age of the housing stock — it says nothing about any individual home, most of which have been updated many times. The plumbing section above is education, not a diagnosis.
How often does this update? With each annual ACS 5-year release. Rankings from different ACS vintages are never mixed in one table, and prior editions stay archived.
Can our city use the badge without linking to this page? Yes. The embed snippet links here because that’s the convenient default, but the ranking is not conditioned on posting, linking, or anything else.
Full methodology
This methodology was fixed in writing before the data pull was run (program spec: Census ACS tables B25034 / B25035, minimum place size so percentages are stable, margins of error published with the data). The ranking rules below were not adjusted after seeing which cities won.
1. Data source
- Dataset: U.S. Census Bureau, American Community Survey (ACS) 2024 5-year estimates, accessed via the Census API and the table-based ACS summary files.
- Tables used:
- B25034 — Year Structure Built: housing units by the period in which the structure was built. The study’s headline metric uses this table’s oldest category, “1939 or earlier.”
- B25035 — Median Year Structure Built: the median (midpoint) year in which a place’s housing structures were built.
- B01003 — Total Population: used only to define the population-based fields (the five largest cities, the 500,000–1,000,000 class, and the 250,000+ median-year field).
- Pull date: October 22, 2026. All figures in this edition come from the single ACS 2024 5-year vintage; figures from different ACS vintages are never mixed in one table.
- Coverage of the pull: all 1,862 Texas Census places were pulled; ranked fields were then limited by the floor in §2.
2. Universe and size floor
- Included in ranked fields: Census places with 10,000 or more housing units (per B25034’s total-units count).
- The floor exists so every published percentage rests on a substantial base — a pre-1940 share computed on a few hundred homes swings wildly with a handful of survey responses; on 10,000+ homes it is stable enough to rank.
- Places below the floor appear in the downloadable data but are not ranked and are not contacted.
- Geography is the Census place (incorporated place / census-designated place as defined by the Bureau). Metro fields assign each place to its Census CBSA by place centroid: Dallas–Fort Worth (19100) and San Antonio–New Braunfels (41700).
3. Metric definitions
- Pre-1940 share = (housing units in B25034’s “1939 or earlier” category) ÷ (total housing units in B25034), expressed as a percentage. Counts are published alongside every share in the ranked tables.
- “Pre-1940” throughout the study means the ACS category as published — built 1939 or earlier. The study does not re-bucket ACS categories or estimate a different cutoff.
- Median year built = B25035 as published: the year such that half of a place’s housing units were built in or before it and half in or after it.
- Worked examples, so the arithmetic is auditable:
- Fort Worth: 20,898 ÷ 373,948 = 5.59%
- San Antonio: 31,158 ÷ 612,901 = 5.08%
- New Braunfels: 1,367 ÷ 44,517 = 3.07%
- Dallas: 30,041 pre-1940 units at the published share of 5.09% (total-units denominator as published in the pulled tables; the share recomputes consistently against it).
4. Fields (fixed before the pull)
- Five largest cities: the five Texas places with the largest B01003 population — Houston, San Antonio, Dallas, Fort Worth, and Austin, as a set. Ranked by pre-1940 share.
- Size class: places with population 500,000–1,000,000, ranked by pre-1940 share. Three places qualify at the floor: Fort Worth, El Paso, Austin.
- Median-year field: places with population 250,000 or more, ranked by median year built, oldest first.
- Metro editions: all places at the §2 floor within the CBSA, ranked by pre-1940 share. The San Antonio metro field contains 8 qualifying places; the Dallas–Fort Worth metro table published in this edition enumerates the top three finishers (the full field ships in the downloadable data).
5. Ranking rules
- Share fields rank high to low by pre-1940 share.
- The median-year field ranks oldest (lowest year) first.
- Ties: two places with the same published median year (Houston and Corpus Christi, both 1982) are listed together at the same position — no tie-break is invented to separate identical published values.
- Every evaluated place at the floor appears in the downloadable data with its figures, ranked or not — no silent omissions. Outreach, however, goes only to podium finishers (top 3 of a field) that are verified publisher entities in the program’s census.
6. Verification notes
- Each published share was recomputed from the published counts (see §3 examples) and matches to the hundredth of a percentage point.
- City results were cross-checked against the same tables as displayed on data.census.gov for the named places before this edition was finalized.
- Where the source pass did not carry a figure — for example, total housing units for Dallas, Houston, and Austin in the big-city table, or pre-1940 counts for Houston and Austin — the study prints “—” rather than deriving, estimating, or back-computing a value. The full pulled tables ship in the downloadable CSV at page build.
7. Limitations — printed, not buried
- The ACS is a survey, not a census of record. Every figure is an estimate with a margin of error, published in the downloadable data. The closest call in this edition: Dallas (5.09%) vs. San Antonio (5.08%) on pre-1940 share in the big-city table — a gap of 0.01 percentage points, far inside any plausible margin of error. The study presents them as effectively tied for second and does not rest any headline on the difference. Fort Worth’s first-place margin (5.59% vs. ~5.1%, on bases of roughly 374,000–613,000 homes) does not turn on a within-margin gap.
- Year built is survey-reported. For older structures especially, the reported year can be approximate (owner and assessor knowledge varies). The pre-1940 category is the Bureau’s broadest and most stable bucket, which is one reason the study uses it as-is.
- Housing age is not plumbing age. This study measures the age of a place’s housing structures. Individual homes are re-piped, re-wired, and re-equipped over their lives; nothing in these tables describes the current plumbing of any specific home. The study page’s plumbing section is general education about housing of this era, not a per-home or per-city condition claim.
- Vintage discipline. ACS 2024 5-year estimates describe the 2020–2024 survey period. A place’s position can move between vintages as new construction dilutes the old-stock share — that is a real change in the stock, not an error, and editions are never blended.
8. Corrections policy
If any figure for your city looks wrong, contact the research team at [email protected]. Corrections are verified against the published ACS tables, applied to the page and the downloadable data, and logged in a public corrections log with dates. A correction never requires a city to post, link, or pay anything.
9. Refresh and archiving
This study re-runs on each annual ACS 5-year release. Prior editions remain archived at dated URLs. A city that enters or leaves a podium does so only through a new edition under this same methodology.
