How Old Is My House? 6 Ways to Find the Year Built
How old is my house? Find the year built with the county assessor, permits and deeds, then check clues inside the house. Records vary by state.
In this article
Quick answer: Start with the county or city office that taxes your property (the assessor, appraisal district or property appraiser) and look up your address for the year built. Then cross-check it against your closing papers, building permits and a certificate of occupancy, because tax records and listing sites can be wrong or can show a renovation year instead. Where records are thin, clues inside the house can narrow the range.
Why your home's age matters
Age is the quickest predictor of what is hiding in your walls and what will wear out next. Based on American Community Survey data, the National Association of Home Builders (NAHB) puts the median age of owner-occupied homes at 41 years in 2023, and about 48% were built before 1980.
The year built also shapes:
- Materials and hazards. Lead paint, old wiring and certain plumbing materials all track to specific eras (see the table below).
- System lifespans. If you have no install dates, the house's age is your first estimate for the roof, wiring and plumbing. For an individual unit, see how to tell how old your water heater is.
- Insurance and resale. Insurers and buyers often ask for the year built and for updates to the roof, wiring and plumbing, so it helps to have it right.
How to find your home's year built, step by step
- Check your closing file. The appraisal, seller's disclosure and inspection report from your purchase usually state the year built.
- Search the property tax office. Find your county assessor, appraisal district or property appraiser online and search by address or parcel number. Most show "year built" along with square footage and lot size.
- Ask the building department for permits. The city or county permit office can tell you what permits were issued for the address. The earliest one is often the original building permit, and the certificate of occupancy (CO) records when the building was first approved for use.
- Trace the deed. The county recorder or registry of deeds holds sales and subdivision records. A lot that was platted in a given year tells you the house is no older than that.
- Compare listing sites. Zillow, Redfin and Realtor.com show year built, but treat it as a cross-check. Zillow says its figures combine public records and user-submitted data, so an old error can be repeated.
- For older homes, use historical sources. Library of Congress Sanborn fire insurance maps cover more than 10,000 US communities over about 150 years. City directories, historic district surveys and your state historic preservation office can also date a building.
Which source to trust
| Source | What it tells you | Watch out for |
|---|---|---|
| Closing documents | Year built as of your purchase | Usually copied from tax or listing data |
| Assessor or appraisal district | Year built, size, lot | May be an "effective" year, or estimated |
| Building permits / CO | Dates work was approved | Old records can be missing or not online |
| Deeds and plats | When the lot was created | Does not date the house itself |
| Listing sites | Quick cross-check | Public record plus user-submitted data |
| Sanborn maps, historic surveys | Whether a building existed on a given date | Coverage varies by town |
How this varies by state and county
There is no national database of building dates. Each county, city or town keeps its own records, so what you can find depends on where you live.
- Different offices, different names. Examples include the Cook County Assessor in Illinois, the Los Angeles County Assessor in California, the Harris Central Appraisal District in Texas and the Broward County Property Appraiser in Florida. In many New England towns the local assessor and the registry of deeds are separate offices.
- Permits live with the city or county. New York City's Department of Buildings, for example, runs an online Building Information Search for permits and certificates of occupancy, but filings made in its newer DOB NOW system sit in a separate portal.
- Older records may be offline. In Massachusetts, one town notes that much of the 20th century's deeds are digitized, while earlier ones require an in-person visit, and the state's MACRIS database holds historic building inventory forms. Call the office if a search comes up empty.
- The date means different things. The Broward County Property Appraiser explains that its effective year built generally reflects the tax year the building value was first added to the roll, may change after major renovation, and should not replace official building department records.
When two sources disagree, the building department's original permit or certificate of occupancy is generally the stronger evidence.
Clues inside the house
If records are missing, physical clues can bracket a date. None is exact, and renovations can mix eras.
- Toilet tank. A manufacture date is often stamped inside the tank or under the lid. It dates the toilet, so it only gives a "no earlier than" for the house.
- Wiring and panel. Look for ungrounded two-prong outlets, cloth-covered wiring or aluminum wiring, and check dates on the panel and permit stickers.
- Plumbing. Gray flexible plastic pipe, galvanized steel or lead supply lines point to specific eras.
- Water heater, furnace and appliances. Serial numbers usually encode a build date, and the water heater guide above shows how to read one.
- Walls and windows. Plaster over wood lath versus drywall, and single-pane versus sealed double-pane windows, suggest whether major parts were updated.
The house is often older than its equipment. The water heater, furnace and air conditioner were usually replaced at some point, and their serial numbers date the unit, not the house. To read those, see how to find an appliance serial number and read its date code and the water heater age guide.
What the age tells you to check
These are rough eras, not guarantees. A renovation may have replaced the old materials, and the reverse can also happen.
| Era or year built | What to look for | Source |
|---|---|---|
| Before 1978 | Lead-based paint. Federal rules require sellers to disclose known lead paint and give buyers a pamphlet and a chance to inspect | EPA |
| Before 1986 | Lead pipes, fixtures or solder are more likely in older cities and homes | EPA |
| About 1965 to mid-1970s | Aluminum branch-circuit wiring, which can overheat at connections | CPSC |
| 1978 to mid-1995 | Polybutylene (PB) water pipe, installed in roughly 10 million US homes and prone to internal deterioration | InterNACHI |
| Older materials generally | Asbestos in floor tiles, insulation and roofing, a concern mainly when disturbed | EPA |
| Built 2006 to 2007 | Problem drywall that corrodes metal and smells of sulfur; the Consumer Product Safety Commission (CPSC) received reports from 44 states, most from Florida | CPSC |
Do not scrape, sand or demolish materials you suspect contain lead or asbestos. Hire a qualified professional first. For a broader pre-purchase view, read what a home inspection misses.
Put the year to work
Once you have a reliable year, use it to plan. Ask your insurer which updates they track (see how to lower your homeowner's insurance premium), budget for systems that are due, and keep the permits and records you found.
In Steadwell, entering your address attempts to fill in the year built and other details from public records, and you can correct the year if it looks wrong. Your home's age is then used as a rough estimate for system ages until you add real install dates, and it is labeled as an estimate. Track upkeep in the home maintenance tracker and keep permits, the deed and inspection reports in the home document vault.
Frequently asked questions
Where is the most reliable place to find the year my house was built?
The original building permit or certificate of occupancy from your local building department is usually the strongest evidence. Tax records are the fastest starting point, but they can be estimates.
Why does Zillow show a different year than the county?
Listing sites combine public records with user-submitted and listing data, and tax offices sometimes record an "effective" year after a renovation. Check both against your permits, and ask the county to correct clear errors.
Can I find the age of my house without going to the county?
Often yes. Many assessors and appraisal districts have free online address search, and closing documents are a quick first check. If nothing turns up, call the assessor or building department or visit in person.
Do all states keep the same records?
No. The office names, what is online and how far back records go all vary by county and state. Ask your county assessor, recorder or registry of deeds, and your local building department.
My house is older than any record I can find. What now?
Use historical maps such as Sanborn maps, deed chains, city directories and your state historic preservation office, and consider a home inspector who can read construction clues. Expect a range of years rather than an exact date.
How do I find the age of a house by address?
Search the website of the county assessor, appraisal district or property appraiser for your street address or parcel number. Most list the year built along with square footage and lot size. Then confirm it with the original building permit or certificate of occupancy from the local building department, since tax records can be estimates.
Can I look up building permits for my house online?
Often, but it depends on the city or county. Some building departments have an online permit search. New York City's Department of Buildings, for example, runs a Building Information Search for permits and certificates of occupancy, though filings in its newer DOB NOW system sit in a separate portal. Where nothing is online, call the permit office and ask how to request the records for your address.
What does effective year built mean?
It is a tax-roll figure, not always the year the house was constructed. The Broward County Property Appraiser explains that its effective year built generally reflects the tax year the building value was first added to the roll, may change after major renovation, and should not replace official building department records.