When you buy a condo in Tokyo, three things sit on the same table: the disaster risk of the land, the insurance you can buy against it, and the long-term repair plan (長期修繕計画) of the building. Most buyers treat them as separate checklists. They are not. Each one feeds the other, and the price you pay should reflect all three.
At RE : public, we read these documents in pairs. A flood-zone address changes how we read the repair plan. A weak repair plan changes how we read the insurance quote. This article shows you how to do the same.
Why these three documents move together
A Tokyo condo is exposed to four main hazards: earthquakes, fires, wind and water (typhoons, river flooding, inland flooding), and aging of the building itself. The first three are mostly covered by insurance. The fourth is covered — or not — by the long-term repair plan and the reserve fund (修繕積立金).
Here is the link buyers miss:
- Disaster risk sets the baseline probability of damage.
- Insurance transfers part of that risk in exchange for premiums.
- The repair plan decides whether the building can absorb the part insurance does not cover.
If any one of the three is weak, the other two have to work harder. If two are weak, your monthly cost goes up, your resale tendency softens, and your downside risk widens.
Reading the disaster risk of the address
Before you look at the building, look at the ground.
Hazard maps you should pull
Tokyo's 23 wards and surrounding cities all publish hazard maps. The Ministry of Land, Infrastructure, Transport and Tourism (国土交通省) also runs a unified portal called the Hazard Map Portal Site (ハザードマップポータルサイト). You want at least these layers:
- Flood inundation depth for major rivers (洪水浸水想定区域)
- Inland flooding from rainfall overwhelming sewers (内水氾濫)
- Storm surge for low-lying bayside wards (高潮浸水想定区域)
- Liquefaction tendency (液状化マップ)
- Earthquake shaking and building collapse risk by district, published by the Tokyo Metropolitan Government (東京都地震に関する地域危険度測定調査)
- Tsunami for coastal areas
- Landslide and steep-slope hazard zones (土砂災害警戒区域)
A clean address is not one with zero hazard. It is one where the hazards are known, mapped, and matched by the building's design.
What "matched by design" means
A unit on the 12th floor in a 3-meter inundation zone is not exposed to flood damage in the unit itself. But the building's electrical room, elevator pit, parking, and entrance often are. Ask:
- Where are the main electrical panels and the emergency generator?
- Is the elevator machine room on the roof or in the basement?
- Are there flood barriers (止水板) at entrances and parking ramps?
- For tall buildings, is the structure long-period ground motion conscious (長周期地震動対策)?
These answers turn an abstract hazard map into a concrete repair-plan question: has the management association budgeted for the upgrades the hazard map implies?
Earthquake exposure: building age and the 1981 line
Japan's building code was overhauled on 1 June 1981. The "new earthquake standard" (新耐震基準) applies to buildings whose construction permit was issued on or after that date. A further refinement came in 2000 for wood-frame buildings, less relevant for condos.
Our analysis result, repeated across hundreds of Tokyo listings:
- Pre-1981 buildings trade at a discount, but the discount is often smaller than the seismic risk and the insurance premium gap suggest. Earthquake insurance (地震保険) is more expensive, and lenders may be cautious.
- 1981–2000 buildings are the largest pool. Quality varies. Look for whether a seismic diagnosis (耐震診断) has been done and whether retrofitting (耐震改修) is in the repair plan.
- Post-2000 buildings generally pass current expectations, but base isolation (免震) and damping (制振) systems vary widely. Base isolation reduces shaking but adds maintenance items to the long-term repair plan — bearings and dampers need inspection and eventual replacement.
The point: a newer building is not automatically safer in total cost of ownership. A base-isolated tower has lower earthquake risk but a heavier repair plan. A 1985 building with a completed retrofit and a fully funded reserve can be a better risk than a 2008 building with a thin reserve.
Insurance: what it covers, what it does not
In Japan, residential property insurance for a condo unit is split into two main products.
Fire insurance (火災保険)
Despite the name, this is the broad property policy. A typical condo policy covers:
- Fire, lightning, explosion
- Wind, hail, snow damage
- Water damage from burst pipes (within your unit)
- Flood damage, if you opt in (and meet depth/height triggers)
- Theft, accidental breakage (optional riders)
Two things to check:
- The flood rider (水災補償). It is optional. In low-risk areas, buyers often drop it to save premium. In a mapped inundation zone, dropping it is a risk you are taking knowingly, not a saving.
- The insured object scope. Your policy covers the 専有部分 — the inside of your unit, typically from the inner surface of the structural walls. The common areas (共用部分) are covered by a separate policy held by the management association.
Earthquake insurance (地震保険)
This is a government-backed rider attached to fire insurance. You cannot buy it standalone. Key features:
- Maximum payout is 50% of the fire insurance sum insured, capped at 50 million yen for the building portion and 10 million yen for contents.
- Premium depends on prefecture and building structure. Tokyo is in a higher-premium tier.
- Discounts apply for new earthquake standard, seismic grade certifications (耐震等級), base isolation, and year of construction.
Earthquake insurance is not designed to rebuild your unit. It is designed to give you liquidity after a major event. Read it as a cash-flow tool, not a reconstruction tool.
The gap insurance does not fill
Common-area damage beyond the association's policy limits, special assessments after a disaster, loss of rent during repairs, and depreciation of the building's market reputation — none of these are fully covered. This is where the repair plan comes back in.
The long-term repair plan: the document buyers underread
Every condo association is expected to maintain a long-term repair plan, typically on a 30-year horizon, updated every five years or so. The Ministry of Land, Infrastructure, Transport and Tourism publishes guidelines (長期修繕計画作成ガイドライン) that set the format most associations follow.
When we review one, we look at six things.
1. The reserve fund balance per unit
Divide the total reserve fund (修繕積立金残高) by the number of units, then by the average専有面積. Compare to the building's age. A 20-year-old building with a thin per-square-meter reserve is a warning, not a deal-breaker — but it changes the price.
2. The reserve fund contribution curve
Many older plans use a stepped-up schedule (段階増額方式): low contributions early, large hikes later. If you buy just before a scheduled hike, your monthly cost will jump. A flat schedule (均等積立方式) is more honest and is what current MLIT guidance prefers.
3. Major repair cycles
Standard cycles in Japan:
- Exterior wall and waterproofing (大規模修繕): roughly every 12–15 years
- Roof waterproofing: 12–15 years
- Elevator modernization: 25–30 years
- Mechanical parking: 15–20 years per major overhaul
- Water supply and drainage piping: 25–30 years for replacement
Check which cycles have been completed, which are upcoming, and whether the plan's cost estimates look current. Construction costs in Tokyo have risen sharply in recent years, and plans written before that have stale numbers.
4. Special assessments and loans
Read the past general meeting minutes (総会議事録) for the last three to five years. Look for:
- Any one-time assessments (一時金)
- Any association borrowing
- Disputes over the repair plan or the management company
A building that has already done its first and second large-scale repairs without drama tends to repeat that pattern.
5. Disaster-related items in the plan
This is the connection point. Does the plan include:
- Flood barriers and waterproofing of basement entries, if the address is in a flood zone?
- Seismic retrofitting, if the building is pre-1981 or has a known weakness?
- Backup generator fuel and battery replacement cycles?
- Long-period ground motion items, for tall buildings?
If the hazard map flags a risk and the repair plan ignores it, the gap will eventually be filled by a special assessment. Price that in.
6. The management company and the board
A self-managed association (自主管理) is not automatically bad, but it requires an active board. A building with a major management company and an engaged board is the typical baseline. A building with a passive board and rotating management contracts is a softer risk.
Putting the three together: a working checklist
Before you sign, run this sequence.
- Pull the hazard maps for the exact address. Note every flagged layer.
- For each flagged hazard, find the corresponding line in the long-term repair plan. If missing, ask why.
- Get the fire insurance and earthquake insurance quotes with and without the flood rider, and with the relevant seismic discounts applied.
- Compare the per-square-meter reserve fund balance to similar-age buildings in the ward.
- Read the last three years of general meeting minutes.
- Add expected monthly management fee (管理費), reserve fund contribution, insurance premium, and a reserve for special assessments. That is your real monthly cost — not the listed one.
A reference estimate of total monthly cost built this way is usually 10 to 25 percent higher than what the listing implies. That is not a reason to walk away. It is a reason to negotiate, or to choose a building where the gap is smaller.
A short example
Two buildings, both in Koto Ward (江東区), both 70㎡, both around 80 million yen asking.
- Building A: built 2015, base-isolated, in a 3m inundation zone. Repair plan includes flood barriers, generator on the second floor, and a flat reserve schedule. Insurance: standard fire with flood rider, mid-tier earthquake premium (base isolation discount).
- Building B: built 2003, conventional structure, same flood zone. Repair plan has no flood items, stepped-up reserve with a hike scheduled in two years, and the first large-scale repair was delayed. Insurance: similar fire premium, slightly lower earthquake premium without the base isolation discount.
On the listing, B looks cheaper to own. After the analysis, A's tendency is a more stable monthly cost and a narrower downside in a major event. B may still be the right choice — at a lower price.
What RE : public does
We read the hazard maps, the repair plan, the minutes, and the insurance quotes as one package. We give you a reference estimate of total monthly cost, the items most likely to trigger a special assessment, and the negotiation points the seller's side rarely volunteers. We do not sell the property. We do not earn a brokerage fee. That is the point.
This is not investment advice. The final decision is yours.