How to Find the Year Your House Was Built

Six ways to pin down the year, in order of effort

1. Check the county property appraiser or assessor website: search the address and read the "year built" or "effective year built" field — free and definitive in most U.S. counties.
2. Pull the permit history from the city or county building department portal: the original building permit carries the construction date, and later permits date every major remodel.
3. Read the utility clues on site: electric meters, water heaters and furnaces carry date codes, and the inside of a toilet tank lid is usually stamped with its manufacture month and year.
4. Look for a plat map or subdivision date: the recorded plat year sets the earliest possible build year for a tract home.
5. For pre-1950 houses, check Sanborn fire insurance maps (digitized by the Library of Congress and many university libraries) — they show building footprints decade by decade.
6. Cross-check with the deed chain or the seller disclosure: listing sites repeat assessor data, so verify against the primary record when the number matters.

Watch for these traps

• "Effective year built" is not the build year. Assessors update it after major renovations — use the original year for era checklists, and the effective year as a remodel clue.
• Additions have their own years. A 1955 house with a 1988 addition needs both checklists: the addition can contain polybutylene while the main house has galvanized pipe.
• Boundary years cut both ways. If the records say 1977–1979, run the checklist for each candidate year — this site flags phase-in/out items automatically.