Building Age and Earthquake Safety in Rental Properties—Understanding Old and New Seismic Standards and Safe Property Selection
Older rental properties offer lower rents, but many renters worry about seismic safety. This guide explains the differences between pre-1981 old seismic standard buildings and new seismic standard buildings, how to verify seismic retrofitting, and key tips for selecting safe properties.
Japan's Building Standard Law establishes "seismic standards" as strength criteria for buildings against earthquakes. These standards underwent a major revision on June 1, 1981 (Showa 56), with pre-1981 standards called "old seismic standards" and post-1981 standards called "new seismic standards."
Old Seismic Standards (Building permits issued before May 31, 1981)
Buildings are designed to withstand earthquakes of approximately Magnitude 5 Strong without collapse. The standards were revised following significant damage from the 1978 Miyagi Prefecture Offshore Earthquake.
Buildings are designed to withstand major earthquakes of Magnitude 6 Strong to 7 without collapse. During the 1995 Great Hanshin-Awaji Earthquake, most buildings meeting the new seismic standards avoided collapse, while damage concentrated on buildings built under the old standards.
New Seismic Standards (Building permits issued after June 1, 1981)
Further Strengthening: 2000 Standards
On June 1, 2000, seismic standards for wooden houses were further strengthened. New regulations added metal hardware requirements for joints and specified foundation designs, significantly improving the seismic resilience of wooden structures.
Building Age and Seismic Safety Guidelines
Completion Year
Seismic Standard
Overview
Up to May 1981
Old Seismic
Design standard for Magnitude 5 Strong
June 1981–1999
New Seismic (wooden structures retain some old standard elements)
Designed not to collapse in Magnitude 6 Strong–7 earthquakes
2000 and later
New Seismic (strengthened for wooden structures)
Added strength standards for wooden joint connections and foundations
As a general guideline, properties completed before 1981 likely meet old seismic standards. However, since the building permit date (design phase) can differ from completion date (move-in ready), accuracy requires checking the official permit certificate issuance date.
Current Conditions and Risks of Old Seismic Standard Buildings
While not all old seismic standard buildings are dangerous, they do carry relatively higher risks during major earthquakes.
Risks of Old Seismic Standard Buildings
•High risk of collapse in major earthquakes (Magnitude 6 Strong or higher)
•Without seismic retrofitting, potential for serious damage comparable to the Great Hanshin-Awaji Earthquake
•Lower appraisal value for sale or mortgage (if purchasing)
When Old Seismic Standard Buildings Are Still Safe
•Seismic diagnostics confirm an IS value (seismic index) of 0.6 or higher
•Seismic reinforcement work (such as added walls or metal bracing) has been completed
•Reinforced concrete construction with structurally robust design
Specific Methods to Verify Seismic Safety
There are several ways to verify seismic safety when viewing or before applying for a rental property.
1. Check Building Age from Property Information
Major property portals like SUUMO, HOME'S, and Athome list the year and month of construction. Properties completed in 1982 or later likely meet new seismic standards.
2. Request Seismic Diagnostic Reports from Property Managers or Real Estate Agents
Especially for old seismic standard buildings (pre-1981), confirm whether a seismic diagnostic has been performed. If a report exists, check the IS value (structural seismic index)—0.6 or higher indicates adequate safety.
3. Check Local Government Seismic Retrofit Support Information
Many municipalities offer subsidies for seismic diagnostics and retrofits of old seismic standard buildings. Ask your property manager whether the building has already undergone subsidy-funded improvements.
4. Consider Earthquake and Household Contents Insurance
Even for properties with seismic concerns, household contents and earthquake insurance can reduce financial risk. While building insurance is the landlord's responsibility, renters must purchase their own household contents insurance.
Tips for Choosing Safe Properties
Don't Judge by Building Age Alone
Even buildings meeting new seismic standards (1981 and later) can have reduced seismic resilience due to poor construction or inadequate maintenance. Beyond age, check maintenance conditions, external condition, and cleanliness of common areas.
Reinforced Concrete (RC) Structures Have Relative Advantages
Among buildings of the same era, RC construction generally has better seismic and fire resistance than wooden (W) structures. They also offer better soundproofing and lower collapse risk in major earthquakes.
Check Location Risks Using Hazard Maps
Along with building seismic safety, verify liquefaction risk, landslide risk, and flood risk. The Ministry of Land, Infrastructure, Transport and Tourism operates a hazard map portal where you can search by address.
Check Long-Term Quality Housing Status and Seismic Grade
Newer properties may display a seismic grade (1–3). Properties with seismic grade 3 (1.5 times standard strength) offer the highest safety level and qualify for earthquake insurance discounts.
Summary
Building age and seismic standards are important indicators when evaluating rental property safety. Seismic diagnostic verification is essential for pre-1981 old seismic standard buildings. However, even older buildings can be safe if properly retrofitted. Beyond seeking affordable rent, prioritize seismic safety verification as a key factor in property selection to protect yourself in earthquake-prone Japan.
When selecting a rental property, security is an important consideration alongside floor plan and rent. This article covers practical security measures useful for anyone, especially those living alone or women—from equipment to check during viewings, to using security devices after moving in, and how to respond in emergencies.
