How To Check If A Japanese Property Has Soil Contamination

What actually triggers a soil investigation

The Soil Contamination Countermeasures Act (Act No. 53 of 2002), administered by Japan's Ministry of the Environment, does not require every parcel of land to be tested. A formal investigation is triggered in three main ways:

• Closing a facility that used designated hazardous substances (Article 3): when a "facility using specified hazardous substances" (有害物質使用特定施設 — a narrower category than "any business that happens to store a hazardous chemical." It means a facility that is itself a specified facility under the Water Pollution Control Act and uses, manufactures, or processes one of the law's 26 designated hazardous substances — plating works and dry cleaners are common examples) is discontinued, the landowner must have a certified investigation agency survey the site and report the results to the prefectural governor — unless the governor confirms in advance that the land's planned future use poses no health risk, which defers the survey rather than waiving it. An ordinary retail gas station does not fall into this category on its own — storing and dispensing gasoline is not treated as "using" the benzene it contains — so a former gas station's closure does not, by itself, trigger an Article 3 survey; contamination there is still a real due-diligence concern, just not through this particular legal trigger.
• A large-scale change to the land's form (Article 4): before making a large-scale excavation or fill covering 3,000 m² or more of ordinary land — or 900 m² or more on the site of a factory that used hazardous-substance facilities — the landowner must notify the prefectural governor at least 30 days ahead of the work. A narrow exemption applies only when all three conditions are met together: no excavated soil leaves the site, no soil scatters or runs off the site, and the change is shallower than 50 cm everywhere. Working shallow alone does not avoid the requirement — a 40 cm-deep excavation that trucks soil off site can still need the 30-day notice. If the governor suspects contamination based on the site's history, a survey can be ordered as part of that process.
• A suspected health risk the governor identifies independently (Article 5): even without a facility closure or a large excavation, a prefectural governor who finds specific reason to suspect contamination poses a health risk can order the landowner to have a designated agency investigate.

An ordinary residential resale with no industrial history and no large-scale excavation planned may simply never trigger a mandatory survey under any of these three routes — which is exactly why relying on "no known survey" as proof of clean land is a mistake.

What happens once contamination is confirmed

If a survey (mandatory or voluntary) finds contamination by a designated hazardous substance above the standards set by the Ministry of the Environment, the prefectural governor designates the parcel into one of two categories, not on the touki record but in a separate environmental register:

• 要措置区域 (Article 6, "area requiring measures"): used when contamination exceeds the standard and there is an identified route of exposure — for example, contaminated groundwater used as drinking water nearby. The governor directs the landowner to take specific countermeasures (excavation and removal, containment, capping, or blocking the exposure pathway) by a set deadline.
• 形質変更時要届出区域 (Article 11, "area requiring notification upon change of form and quality"): used when contamination exceeds the standard but no exposure route currently exists — commonly because the site is paved over or otherwise not in contact with people. No cleanup is ordered immediately, but any future excavation or land-form change on the parcel must be notified to the governor in advance, indefinitely, until the designation is lifted.

Both designations are recorded in a public register (台帳) kept by the prefectural or, in many cities, municipal environmental affairs division — some, including Tokyo, publish a searchable online system. Designation is about documented contamination that has actually been measured against a legal standard; it says nothing about parcels that have simply never been tested.

Why the registration record will not show any of this

The touki record's 表題部 (property description), 甲区 (ownership), and 乙区 (other rights, e.g. mortgages) sections describe legal status under the Real Property Registration Act — soil contamination designation is an entirely separate administrative system under the Ministry of the Environment, not something the Legal Affairs Bureau records against title. Ordering a clean registration record with no mortgages, seizures, or other encumbrances tells you nothing about whether the land is inside a designated area.

What the registration record can offer are indirect clues, not proof: 地目 (the registered land category) sometimes reads 雑種地 ("miscellaneous land") on parcels with an unusual prior use, and a building's own registration record states 種類 (building type) — entries like 工場 (factory) or 給油所 (gas station) are a direct signal to dig further into that parcel's history, even though the registered type alone does not confirm contamination one way or the other.

Here is a practical way to check before you get attached to a listing:

1. Ask directly about the land's prior use, not just its current listing description. A "vacant lot ready to build" description tells you nothing about whether a gas station or plating factory stood there twenty years ago. Old maps, aerial photos, and long-time neighbors are standard sources for this kind of history check (地歴調査, chireki chousa) in Japan.
2. Check the prefectural or municipal designated-areas register for the parcel. Contact the environmental affairs division of the prefecture (and city, for larger municipalities) where the property sits, or use an online system if the area publishes one, to see whether the parcel is currently listed as 要措置区域 or 形質変更時要届出区域.
3. Ask the agent whether the important-matters explanation covers soil contamination. Under Article 35 of the Real Estate Brokerage Act (宅地建物取引業法), the agent must explain material matters affecting the property before you sign; in practice this covers known designation under the Soil Contamination Countermeasures Act and any contamination the seller or agent is otherwise aware of. Ask specifically — do not assume silence means a clean result rather than an untested one.
4. Treat "never tested" and "tested clean" as very different answers. Because a mandatory survey is only triggered by a facility closure, a large excavation, or a governor's independent order, plenty of land — including some former industrial sites where the triggering facility closed decades before the current law existed — has simply never been surveyed. That is not the same as a clean result.
5. Weigh a voluntary survey for higher-risk sites. For land with any factory, gas station, dry cleaner, printing, or plating history, commissioning your own investigation through a designated investigation agency before you commit is a normal part of due diligence in Japan, not an unusual request.
6. Bring in a judicial scrivener (司法書士) or environmental consultant for anything unresolved. Interpreting an existing designation, negotiating who bears remediation cost, or scoping a voluntary survey are exactly the kind of decisions worth a professional opinion rather than a guess.

The most common mistake is assuming that an unremarkable-looking registration record — no mortgage, no seizure, ordinary ownership history — says anything at all about soil condition. It does not, because contamination status is never recorded there in the first place.

What the registration record can and cannot tell you here:

• What it shows reliably: the registered land category (地目) and, for a separate building record, the registered building type (種類) — occasionally a useful clue (工場, 給油所, or 雑種地) that a parcel had an industrial or unusual prior use worth investigating further.
• What it does not show: whether the parcel is currently designated 要措置区域 or 形質変更時要届出区域 under the Soil Contamination Countermeasures Act, whether any survey has ever been conducted, or the results of one if it has. None of that is a registry fact — it comes from the prefectural or municipal environmental affairs division, not the Legal Affairs Bureau.
• How to order the record: On Japan Property Research, locate the parcel by address or lot number and order the land registration record for ¥1,500. If a building on the site is a plausible former industrial use, order that building's registration record as well to check the registered 種類.

A soil contamination flag, confirmed or suspected, does not automatically make a property unbuyable — plenty of remediated former industrial sites are redeveloped and sold normally, and 形質変更時要届出区域 status in particular is common on paved commercial land with no active exposure risk. But it is a cost and timeline question you want answered before you get attached to a listing, not after. Our Japan property due diligence checklist covers where this check fits alongside ownership, zoning, and boundary review.

FAQ

Does the Japanese property registration record show soil contamination? No. Soil contamination designation under the Soil Contamination Countermeasures Act is a separate administrative register kept by prefectural or municipal environmental affairs divisions, not something the Legal Affairs Bureau records on the touki record's ownership or rights sections.

How do I find out if a property is in a designated contaminated area? Contact the environmental affairs division of the prefecture (and city, for larger municipalities) where the property is located, or check that authority's public register — some, including Tokyo, publish a searchable online system for 要措置区域 and 形質変更時要届出区域 designations.

Is every former factory or gas station site automatically contaminated? No. Designation only follows an actual survey that measures contamination above the legal standard. Many former industrial sites have never been surveyed at all — which is a different, and less certain, situation than a documented clean result.

Do sellers have to disclose known soil contamination? A real estate agent has a duty under Article 35 of the Real Estate Brokerage Act to explain material matters affecting the property before a contract is signed, which in practice covers known contamination designations and other contamination the seller or agent is aware of. Ask directly, since this depends on what is actually known rather than on a universal testing requirement.

Can I still buy land inside a designated area? Often, yes. 形質変更時要届出区域 status mainly adds a notification step before any future excavation, without requiring immediate cleanup. 要措置区域 status is more serious, since it means the governor has ordered specific remediation measures — factor the cost, responsible party, and timeline for those measures into your decision before committing.

Related guides:

• How To Read A Japanese Property Registration Record
• How To Check If A Japanese Property Is Farmland
• How To Check Zoning And Hazard Maps In Japan
• Japan Property Due Diligence Checklist
• How To Order A Japan Property Registration Record In English

• Soil Contamination Countermeasures Act (土壌汚染対策法), Act No. 53 of 2002 — Ministry of Justice, Japanese Law Translation
• Overview of the Soil Contamination Countermeasures Act — Article 3, 4, 5, 6, and 11 procedures — Tokyo Metropolitan Government, Bureau of Environment
• Designation status of areas requiring measures / notification (要措置区域等の指定状況) — Tokyo Metropolitan Government, Bureau of Environment
• 要措置区域（法第６条）と形質変更時要届出区域（法第１１条） — Hyogo Prefectural Government, Department of Environment
• Soil Contamination Countermeasures Act procedures for facility closure (法第3条関係) — Kumamoto Prefectural Government
• What is a "facility using specified hazardous substances"? — confirms an ordinary gas station is not one — Yokohama City Government
• Article 4 notification for land-form changes of 3,000 m² or more — scope and the narrow shallow-excavation exemption — Kagoshima Prefectural Government
• Real Estate Brokerage Act (宅地建物取引業法), Article 35 — explanation of important matters — Ministry of Justice, Japanese Law Translation