New apartment has defects. Is there a 10-year warranty?

What the Law Says

Japan’s housing warranty system is governed by the Act on Promotion of Quality Assurance in Housing (Housing Quality Assurance Act). It establishes mandatory warranty obligations for sellers and builders of new residential buildings, with different timeframes depending on the nature of the defect.

Under this law, sellers and builders must guarantee that new residential buildings are free from defects in 'structural components' and 'components essential to earthquake resistance' for 10 years from delivery. This includes load-bearing walls, columns, beams, foundations, and other parts critical to the building’s structural integrity and seismic safety.

For other defects — such as water leakage, finish flaws, or non-structural equipment failures — the law requires a minimum 2-year warranty. However, parties may agree to extend this to up to 5 years for certain non-structural items, though 5 years is not mandatory.

The warranty applies automatically — no separate contract clause is needed for the 10-year coverage of structural/seismic defects. The seller or builder remains liable even if they go out of business, because the law requires them to join a government-approved warranty insurance or deposit security.

Statutory Text

The seller shall guarantee that the residential building is free from defects in structural components and components essential to earthquake resistance for a period of ten years from the date of delivery.

— Act on Promotion of Quality Assurance in Housing, s. 6 — Guarantee of Defects in Structural Components

Statutory Text

The seller shall guarantee that the residential building is free from defects other than those referred to in the preceding paragraph for a period of not less than two years from the date of delivery.

— Act on Promotion of Quality Assurance in Housing, s. 7 — Guarantee of Other Defects

What to Do

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