Enter the year a US house was built to see which materials and risks are likely for that era, system by system: plumbing, hazardous materials, electrical and heating, and exterior. Each item shows how likely it is, what to ask your home inspector or the seller, and the official source behind the date.
Don’t know the year? Check the “year built” line in the listing or your county property record.
How to read your results
- High: the material was typical for homes of that era according to the cited source. Assume it may be present until someone checks.
- Medium: it was used during that period, but not in most homes, or its use was regional.
- Low: possible but uncommon for that year, or at the edges of the period when it was used.
The rating describes the build year, not your specific house. Renovations, additions and repairs change what is behind the walls. A 1925 house rewired in 1990 may have no knob-and-tube left, and a 1990 house may have older materials reused from stock.
What to do with the list
- Bring it to the home inspection and ask the inspector to look specifically at the high and medium items.
- Ask the seller about past repiping, rewiring, sewer line replacement and any testing for lead or asbestos.
- Ask your insurer early whether knob-and-tube wiring, polybutylene pipe or an older electrical panel affects coverage.
- Do not cut, sand, scrape or sample materials you suspect contain asbestos or lead. EPA advises leaving undamaged material alone and using trained, accredited professionals for testing and removal (EPA).
- Leave any electrical evaluation or repair to a licensed electrician.
Where the dates come from
Every date in the decoder comes from a public source such as the EPA, CPSC, HUD or a local water or building authority. You can see every date and its source in one table on the Sources page, and how the ratings are assigned on the Methodology page.
This tool provides general information only. It is not a home inspection and does not replace a licensed inspector, electrician, plumber or accredited lead or asbestos professional. See our Disclaimer.