Lead-based paint disclosure is required for residential properties built before:

Properties built before 1950 are certainly subject to lead paint disclosure, but this date is too early. The federal mandate specifically applies to properties built before 1978, making 1950 an incomplete answer that doesn't capture the full scope of the regulation.

Properties built before 1990 are not covered by the federal lead paint disclosure requirement. By 1990, lead paint had already been banned for over a decade, so this date is too recent and misses the actual regulatory cutoff.

Properties built before 2000 are definitely not covered by the federal lead paint disclosure requirement. This date is too recent by two decades from the actual 1978 cutoff when lead paint was banned.