For any owner of Japanese rental property, natural deterioration — keinen rekka (経年劣化) in Japanese property-management terminology — is an unavoidable reality of running a leasing business. This is a distinctively Japanese legal and administrative framework: unlike many Western jurisdictions, where the line between an owner’s and a tenant’s repair obligations is often left to lease boilerplate or case-by-case negotiation, Japan has a government-published, nationally referenced standard — the Ministry of Land, Infrastructure, Transport and Tourism’s genjō kaifuku (原状回復, restoration-to-original-condition) guideline — that defines exactly which deterioration is the owner’s responsibility and which is the tenant’s. For international investors acquiring Japanese rental assets, understanding this framework is not an optional footnote; it is central to underwriting maintenance costs, negotiating shikikin (敷金, security deposit) settlements, and forecasting long-term returns. Understanding the definition of natural deterioration, how restoration costs are allocated between owner and tenant, and the management risk of neglecting it is the foundation of stable, professional rental operations. At INA&Associates, we treat repair and maintenance not as a mere cost center but as an investment that protects both the asset’s value and tenant satisfaction. This article systematically organizes the points every owner — and every overseas investor holding or considering Japanese rental property — needs to understand.
What Is Natural Deterioration (Keinen Rekka)?
Keinen rekka (経年劣化, literally “quality decline over the years”) refers to the natural decline in the quality of building materials and fixtures purely as a function of time. It covers not only environmental wear from rain, wind, humidity, temperature swings, and ultraviolet exposure, but also the ordinary soiling and abrasion that comes from everyday habitation. No matter how carefully a tenant lives in a unit, a certain amount of this deterioration is unavoidable once enough years have passed — which is precisely why Japanese law and administrative guidance treat it as the owner’s responsibility rather than the tenant’s fault.
Key Characteristics of Natural Deterioration
Natural deterioration is not damage caused by intent or negligence; it is a gradual decline that occurs within the bounds of ordinary use. Whether a tenant maintained reasonable cleaning and normal use — rather than whose fault the damage technically is — becomes the key test for the cost-allocation rules discussed later in this guide. For this reason, keeping routine maintenance records (photos, inspection notes, repair logs) is a practical habit that helps both owners and tenants avoid disputes at move-out, and it is something international owners managing Japanese property remotely should ask their property manager to maintain systematically.
Areas Most Prone to Deterioration
Within a building, the exterior walls, rooftop waterproofing, water-supply and drainage systems, and plumbing fixtures deteriorate fastest. Because these directly affect both the building’s structural durability and tenants’ daily living conditions, they should be the first priority in any inspection schedule.
- Exterior walls and sealant joints (cracking or peeling)
- Rooftop and balcony waterproofing layers
- Equipment such as water heaters and air conditioners
- Wallpaper (kabegami/cross) and flooring — fading and wear
- Door handles and the moving parts of fittings — wear
Distinguishing Normal Wear, Special Damage, and Natural Deterioration
In practice, three terms are frequently confused: keinen rekka (経年劣化, natural deterioration), tsūjō sonmō (通常損耗, normal wear), and tokubetsu sonmō (特別損耗, special damage). This three-way distinction has no single equivalent in most English-language lease frameworks, where “wear and tear” is typically treated as one broad, negotiable category. In Japan, each of the three terms carries a different, largely non-negotiable allocation of financial responsibility, so getting the definitions precise matters far more than it would under a typical US or UK tenancy agreement.
The Three Terms Compared
| Category | Description | Who Bears the Cost (Principle) |
|---|---|---|
| Natural deterioration (keinen rekka) | Decline in the material’s own quality purely from the passage of time | Owner |
| Normal wear (tsūjō sonmō) | Marks from ordinary use, such as furniture indentations or electrical-appliance scorch marks | Owner |
| Special damage (tokubetsu sonmō) | Damage from intent, negligence, or breach of the tenant’s duty of care (zenkan chūi gimu, 善管注意義務) | Tenant |
Normal wear (tsūjō sonmō) includes things that arise naturally from daily life — a dent in the flooring left by furniture, or a scorch mark on the wall behind a refrigerator. By contrast, continuing to use a fixture after it breaks, making the damage worse, or leaving condensation unaddressed until mold spreads across a wall, is classified as special damage (tokubetsu sonmō), for which the owner can legitimately bill the tenant.
Cases That Qualify as Natural Deterioration
- Flooring wear that has exceeded its expected service life
- Wallpaper scratches that do not penetrate through to the base board
- Equipment that reaches the end of its life through ordinary use
- Sun-fading of walls and wallpaper from sunlight exposure
- Age-related wear on door handles and knobs
Who Is Responsible for Restoration Costs?
Under Japanese practice, responsibility for genjō kaifuku (原状回復, restoration to original condition) is determined case by case, according to the cause of each specific instance of damage, following the framework set out by Japan’s Ministry of Land, Infrastructure, Transport and Tourism — 国土交通省 (Ministry of Land, Infrastructure, Transport and Tourism, MLIT) — in its guideline on “Disputes and Guidelines Concerning Restoration to Original Condition.” The guideline itself is not a statute and carries no direct legal force, but it is so widely cited by Japanese courts when adjudicating deposit disputes that it functions, in effect, as the industry’s operating standard — comparable to how a well-established industry code of practice, rather than a law, can still dictate settlement outcomes in other markets.
Cases the Tenant Must Cover
Damage caused by the tenant’s intent, negligence, or a breach of their duty of care (zenkan chūi gimu, 善管注意義務, the statutory “duty of a good manager”) is subject to restoration charges billed to the tenant. The main examples are as follows.
- Stains from spilled drinks, etc. (from inadequate care of carpeting and similar surfaces)
- Rust stains from leaving a leak under a refrigerator unaddressed
- Graffiti or intentional damage to walls and floors
- Mold that spread because condensation was left unaddressed
- Nicotine staining and odor from smoking
Cases the Owner Must Cover
As a matter of principle, damage arising from natural deterioration and normal wear is the owner’s financial responsibility. Deterioration that inevitably occurs over time, even when the unit was used appropriately, falls within the scope of the owner’s responsibility as the asset holder. If an owner unilaterally deducts these costs from the tenant’s shikikin (敷金, security deposit) — a refundable deposit collected at move-in, structurally similar to but legally distinct from a Western security deposit — it can trigger disputes over the deposit’s return after move-out. Clarifying the cost-allocation rules at the lease-signing stage, rather than after a dispute arises, is what protects trust on both sides — and for an overseas owner working through a Japanese property manager, insisting on this clarity up front is one of the simplest ways to avoid costly disagreements later.
What Japan’s 2020 Civil Code Reform Clarified
Japan’s revised Minpō (民法, Civil Code), which took effect in April 2020, codified — for the first time in statutory text — that a tenant’s restoration obligation excludes both “normal wear” (通常損耗) and “natural deterioration/change over time” (経年変化). This moved what had previously been administrative guidance into a formal legal principle, and it is an important shift for owners and tenants alike: a rule that Japanese courts had already been applying in practice now has direct statutory backing, which strengthens a tenant’s position if an owner attempts to bill for ordinary aging rather than genuine tenant-caused damage.
The Business Risks of Ignoring Natural Deterioration
Deferring maintenance on natural deterioration may look like short-term savings, but over the long run it undermines the very foundation of a rental business. This is a risk international owners should weigh carefully: a Japanese asset that appears to be running efficiently on paper, because visible capital expenditure is low, may in fact be quietly eroding both its physical condition and its market value. The main risks fall into three categories.
Risk 1: Declining Durability and Safety
Accumulated deterioration undermines a building’s structural durability and can endanger tenant safety. A minor flaw in a waterproofing layer, if left untreated, can progress to water leakage and eventually to corrosion of the structural frame itself — at which point the repair cost can balloon to many multiples of what an early fix would have cost. If a safety-related defect is neglected and an accident results, the owner can face liability for a breach of their statutory management responsibility (kanri sekinin, 管理責任) — a legal exposure that follows the property regardless of whether the owner lives in Japan or manages the asset remotely from abroad.
Risk 2: Tenant Dissatisfaction and Turnover
Neglecting repairs degrades day-to-day livability, and tenant dissatisfaction accumulates. As turnover rises, vacancy risk climbs with it, and the stability of rental income suffers. Tenants are highly attuned to how well a building is maintained — in the Japanese rental market, where tenants can typically choose among a large supply of well-kept units even at similar rent levels, visible neglect is one of the fastest ways to lose a tenant at lease renewal.
Risk 3: Rising Vacancy and Falling Asset Value
Prospective tenants tend to choose a clean, well-maintained property even when its rent is somewhat higher than a comparable but neglected one. Ignoring natural deterioration not only lowers occupancy but also directly affects a property’s appraised value at the time of sale — a link that matters just as much to an overseas investor planning an eventual exit as it does to a domestic long-term holder. We believe that rent-setting and physical condition together determine asset value, a point we cover in more depth in our article on how rent strategy and property condition affect asset value.
Warning Signs and Repair Timelines by Building Component
Planning repairs systematically requires understanding the warning signs and renewal-cycle benchmarks for each building component. The figures below are general industry benchmarks only, and will shift depending on the property’s location, structural specifications, and how intensively it is used — climate alone means a coastal or snow-region property in Japan may need attention well before these averages.
Inspection Cycles and Renewal Benchmarks by Component
| Component | Warning Signs | Typical Renewal or Repair Cycle |
|---|---|---|
| Exterior wall paint | Chalking, cracking, fading | Roughly every 10-15 years |
| Rooftop and balcony waterproofing | Blistering, cracking, water staining | Roughly every 10-15 years |
| Water heater | Unstable hot-water flow, unusual noise | Roughly every 10-15 years |
| Wallpaper (kabegami/cross) | Peeling, fading, staining | At each tenant turnover, or roughly every 6 years |
| Air conditioner | Reduced heating/cooling efficiency, water leaks | Roughly every 10-13 years |
When these warning signs are caught early through regular inspection, a partial repair is often enough. The later a problem is discovered, however, the more it tends to spread into adjacent components, expanding the eventual scope — and cost — of the work.
Major Renovations vs. Preventive Maintenance
The basic approach to a maintenance plan rests on two pillars: “major renovation” (taikibo shūzen, 大規模修繕) and “preventive maintenance” (yobō shūzen, 予防修繕). These are not competing strategies; combined, they reduce total lifetime cost — a framework broadly similar to the capital-expenditure-versus-routine-maintenance split familiar to US and European asset managers, though the specific cycles below are shaped by Japan’s climate and building codes.
- Major renovation (taikibo shūzen): Large-scale work that renews the exterior walls, waterproofing, and common areas together in a single project. It is typically carried out on a roughly 10-15 year cycle and presupposes systematic capital reserves set aside in advance.
- Preventive maintenance (yobō shūzen): Targeted work that addresses early signs of a problem before it grows. A small expenditure now prevents major damage later, which in turn reduces the cost of the next major renovation.
For highly specialized work such as waterproofing, the finished quality and service life vary considerably depending on the construction method and the contractor selected. For a framework on choosing between methods, see our article on waterproofing costs and how to choose a contractor. We have collected similar analytical articles in our ina-network article archive.
Repair Cost Benchmarks and Long-Term Maintenance Planning
Repair costs may look like sudden, unplanned expenses, but in practice their timing is reasonably predictable — they are “expected expenditure” rather than a surprise. That predictability is exactly why setting money aside according to a long-term maintenance plan (chōki shūzen keikaku, 長期修繕計画) works so effectively, whether the owner is based in Tokyo or managing the asset remotely from overseas.
Cost Benchmarks
The cost of a major renovation for a typical Japanese rental apartment building varies with its scale and the scope of work, but it is often in the range of several million yen per building (roughly USD 10,000-30,000+, depending on scope, at approximately 155 JPY/USD), and for work that includes both exterior walls and waterproofing, ¥2,000,000-¥3,000,000 (approx. USD 12,900-19,350) is commonly cited as a benchmark. That said, the figure can vary substantially with the number of units, the number of floors, and the degree of deterioration, so we recommend always obtaining quotes from multiple contractors and comparing the itemized breakdown line by line — a discipline that matters even more when an owner cannot inspect the site in person.
How to Build a Long-Term Maintenance Plan
- Inspect the current condition of the building and its equipment, and assess the state of deterioration component by component.
- Using the renewal cycle for each component, map out the expected repair timing for the next 10-30 years.
- Add up the estimated cost of each repair and smooth the resulting expenditure across years.
- Systematically set aside a portion of rental income as a maintenance reserve.
- Review the plan every few years and update it to match the property’s actual condition.
Having a plan in place reduces the anxiety of sudden cash-flow strain and speeds up repair decision-making. The result is that tenant satisfaction and asset value can be preserved at the same time — a combination that, for an internationally diversified investor, also makes the property easier to underwrite and refinance.
The INA&Associates Perspective: A Summary
We position repair and maintenance not as a defensive cost but as an offensive investment. A well-maintained property continues to be chosen by tenants, generating stable long-term income and preserving asset value. Skimping on near-term spending and letting deterioration accumulate eventually comes back as a larger expense and a vacant unit — a dynamic that holds true whether the owner is a Japanese individual investor or an overseas fund holding a single Tokyo asset.
We also believe that explaining the cost-allocation rules honestly to both tenants and owners — including the drawbacks — is the foundation of a trust relationship that lasts. Rental management that every party involved can feel is fair is, in our view, what a genuinely long-term-oriented business looks like. If you are uncertain where to start on a maintenance plan, we recommend beginning with a component-by-component inspection, and working through the priorities together from there.
Frequently Asked Questions
Are Natural Deterioration and Normal Wear the Same Thing?
Strictly speaking, no. Natural deterioration (keinen rekka, 経年劣化) refers to the material itself declining in quality purely due to the passage of time, while normal wear (tsūjō sonmō, 通常損耗) refers to marks that arise naturally from daily life, such as furniture indentations or electrical-appliance scorch marks. Both are, in principle, the owner’s financial responsibility, but understanding the distinction makes it easier to explain a shikikin (敷金, security deposit) settlement clearly to a tenant.
Can I Bill a Tenant for Rust Damage to a Sink?
Rust caused by neglect — for example, leaving a leak unaddressed instead of performing routine upkeep — can be billed to the tenant. Rust that instead results from natural deterioration within the scope of ordinary use, however, is in principle the owner’s responsibility. What matters most in either case is being able to document the cause with photographs and maintenance records, since that evidence is what typically decides the outcome if the allocation is disputed.
How Much Should I Budget for a Major Renovation?
The figure varies substantially with the scope of work and the size of the building, but for work that includes both exterior walls and waterproofing, ¥2,000,000-¥3,000,000 (approx. USD 12,900-19,350 at approximately 155 JPY/USD) is commonly cited as one benchmark. An accurate figure requires a quote based on an on-site survey, so we recommend obtaining quotes from multiple contractors and comparing the itemized breakdown.
How Often Should Preventive Maintenance Be Performed?
A regular inspection roughly once a year is the basic rhythm, with any sign of a problem addressed as early as possible once it is found. Early, low-cost intervention is what ultimately minimizes the total lifetime cost of repairs.
