Converting a former gas station site: how to check the underground tanks and soil

In short: When buying or converting a former gas station site, check three things before signing: (1) whether the underground tanks were removed or left in place, plus the Fire Service Act discontinuation notice; (2) the risk of soil contamination and whether a survey is needed; and (3) whether your intended use can be built under the use district. A gas station's underground tanks and dispensing equipment generally are not a "specified facility using hazardous substances" under the Water Pollution Prevention Act, so closure alone does not, in principle, trigger the Article 3 survey duty under the Soil Contamination Countermeasures Act. The practical entry points are the Article 4 notification, local ordinances, and a voluntary survey in the sale. Permit applications to discontinue or alter hazardous-materials facilities go to an administrative scrivener / the fire department, soil surveys to a designated survey body, registration to a judicial scrivener, and tax to a tax accountant — each referred separately.

This is written for owners who have inherited or acquired a closed gas station site and want to convert it to a warehouse, shop, or roadside store, and for businesses considering the purchase of such a site. We organize the checks on underground tanks and soil from the Fire Service Act, the Soil Contamination Countermeasures Act, and the Building Standards Act, and from public materials. We handle property investigation and sale brokerage; permits, surveys, registration, and tax are each referred to the appropriate professional or specialist.

What should you check first when buying or converting a former gas station site?

Confirm four things from documents before signing: the current state of the underground tanks (removed or left in place), whether the Fire Service Act discontinuation notice was filed, the risk and survey history of soil contamination, and the use district.

Because a gas station handled hazardous materials, storage tanks and piping may remain underground even where the surface looks like vacant land. Judge from the filings and inspection documents and the land's history, not from appearances. The four points to confirm before signing:

Item to check	What to look at	Where to confirm
State of underground tanks	Removed, or left in place (filled with water/sand, etc.). Presence of piping and oil-water separators	Seller, fire department, past drawings
Fire Service Act procedures	Copy of the discontinuation notice (Art. 12-6), past installation permit and completion-inspection certificate	Seller, the fire department with jurisdiction
Risk of soil contamination	Years of operation as a gas station, leak/accident history, past survey results	Seller, municipality, designated survey body
Use district / building limits	Whether the intended use (warehouse, shop, etc.) can be built in that district	Municipal city-planning desk

We can gather and organize these materials as part of our property investigation. The surveys themselves and the permit applications, however, are handled by the relevant professionals and specialists. The fire-safety requirements for newly installing a hazardous-materials facility are covered in Fire-safety requirements for properties usable as hazardous-materials warehouses or gas stations; this article covers the opposite direction — checking a discontinued site.

Why are underground tanks a problem, and what procedures does discontinuation/removal require?

Underground tanks are a hazardous-materials facility, so once use ceases, a discontinuation notice under Article 12-6 of the Fire Service Act is required. Removal of the tank is the rule; even where it must be left in place, the interior must be emptied and safety measures such as filling with water or sand are required.

Dispensing facilities and underground tank storage are hazardous-materials facilities under the Fire Service Act (Act No. 186 of 1948). Installation or alteration requires the permit of the municipal mayor etc. under Article 11(1), and the facility cannot be used until it passes the completion inspection under Article 11(5). The technical standards for location, structure, and equipment are set by the Order for Enforcement of the Act on the Regulation of Hazardous Materials (Cabinet Order No. 306 of 1959): Article 13 for underground tank storage, Article 17 for dispensing facilities.

When use ceases, the owner, manager, or occupant must notify the municipal mayor etc. without delay when the use is discontinued (Fire Service Act, Article 12-6(1)).

Procedure / measure	Content	Basis / who handles it
Discontinuation notice	Notify the municipal mayor etc. without delay once use is discontinued	Fire Service Act Art. 12-6 / document prep by administrative scrivener, filing at the fire department
Removal of hazardous materials	Drain residual fuel from tanks/piping; clean and degas	Removal / safety measures (specialist)
Tank removal	Excavating and removing the tank is the rule	Specialist (with demolition and industrial-waste disposal)
Where it must be left in place	Fill the tank interior with water or sand, etc., per the municipality's review standards	Fire and Disaster Management Agency notices / municipal review standards

Leaving a tank in place does not mean "no removal needed." A tank or contamination left behind creates extra cost and procedures during conversion excavation or a buyer's re-survey. Confirm before signing that the installation permit, completion-inspection certificate, and discontinuation-notice copy are all on hand. For how to sell a demolition-involved site, the thinking in Should an inherited vacant house be sold as cleared land or as land with the old building? is also useful.

Who bears the soil survey duty, and when does it arise?

A gas station's underground tanks and dispensing equipment generally are not a "specified facility using hazardous substances" under the Water Pollution Prevention Act. So closure alone does not, in principle, trigger the Article 3 survey duty under the Soil Contamination Countermeasures Act. The practical entry points are a survey triggered by the Article 4 notification, local ordinances, and a voluntary survey in the sale.

Article 3 of the Soil Contamination Countermeasures Act (Act No. 53 of 2002) requires, when a "specified facility using hazardous substances" under the Water Pollution Prevention Act ceases operation, the land owner etc. to have a soil-contamination survey (by a designated survey body) and to report to the prefectural governor. A gas station's tanks and dispensing equipment usually do not fall under this "specified facility," so the Article 3 mandatory survey does not automatically begin merely because of closure.

What matters in practice are these three:

Trigger	Article / basis	Who / when
Change in the form of land of 3,000 m² or more	Soil Contamination Countermeasures Act Art. 4	The person changing the land form notifies the prefectural governor by 30 days before start; if the governor finds a risk of contamination, a survey is ordered under Art. 5
Local ordinance	Prefectural/municipal environmental ordinances	Some municipalities require their own survey of businesses, such as gas stations, that handled hazardous substances
Voluntary survey in the sale	Agreement of the parties	The buyer typically commissions a designated survey body as due diligence

Rebuilding a site into a warehouse or shop involves excavation and grading, and depending on the area it becomes subject to the Article 4 notification. If there is a gas-station history, the governor may find a contamination risk and order a survey under Article 5. Because which ordinances apply and how much survey is required differ by municipality, treat the specific need for a survey as [unverified] and confirm with the municipality's environmental department and a designated survey body. Soil-contamination surveys are the domain of a designated survey body (specialist); neither we nor the administrative scrivener performs them.

What uses can the site serve under the use district and the Building Standards Act?

What you can build on the site is decided by the use district. Article 48 of the Building Standards Act and Appended Table 2 set the buildings and floor areas allowed per use district, so the feasibility and size cap for warehouses, shops, and workshops change by district.

Gas stations are often on roadsides (along arterial roads) and are frequently in commercial, neighborhood-commercial, quasi-residential, or quasi-industrial districts. When converting the site to another use, first check the use district. Article 48 of the Building Standards Act (Act No. 201 of 1950) restricts the buildings allowed in each use district via Appended Table 2.

Intended use	Main point under the use district
Warehouse (own-use / warehousing business)	Restricted by size/business in residential districts; warehousing-business warehouses mainly in quasi-residential and above
Shop / restaurant	Floor-area cap is tiered by district (e.g., up to 150 m² / up to 500 m² / up to 1,500 m²…)
Roadside store (goods/services)	Whether it exceeds the workshop/shop floor-area limits
Factory / workshop	Which districts allow it varies by motor output and workshop floor area

Whether you build anew from cleared land or use the building for another purpose, the use-district restrictions cannot be sidestepped. Changing the use may also require a change-of-use confirmation application under the Building Standards Act. For reading commercial roadside properties, Requirements for a property usable as a trucking business office and garage and Requirements for a property usable as a certified auto-repair workshop are useful, and for conversion to a restaurant, Exhaust and fire prevention when opening a restaurant in a skeleton property. Confirm individual feasibility at the municipal city-planning / building-guidance desk.

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Who bears the cost of tank removal and soil measures (adjusting it in the sale)?

Removal, survey, and remediation costs can be high, and who bears them greatly changes the effective price. In the sale, decide whether to hand over as-is or to have the seller remove/survey before handover, together with the scope of non-conformity liability.

Underground tank removal, disposal of residual fuel and contaminated soil, and soil survey/remediation all involve orders to specialists and tend to be costly. Because amounts vary greatly with scale and whether contamination exists, this article does not give specific figures (cost ranges are [unverified]; get estimates from removal/survey specialists).

Way of selling	Cost-bearing image	Caution
Hand over as-is (tank left in place)	Buyer bears removal/survey	Price tends to fall; clarify the scope of non-conformity liability
Seller removes/surveys before handover	Seller bears it	Handover takes longer; survey results may add remediation
Build the cost into the price	Apportion between the parties	Share the estimate's premises (remaining items, extent of contamination) in writing

What remains in the ground is a "hidden burden." How non-conformity liability (Civil Code) is set, whether it is an as-is handover, and how far the survey/removal premises are put in writing greatly change later trouble. Because the treatment of buried objects and contamination bears on the important-matters explanation and contract clauses, we organize the issues from the brokerage position. Estimating capital-gains tax or capital-expenditure tax is the domain of a tax accountant; we do not do it. For inherited-land use and sale generally, see also Inheritance consultations.

Who handles what among us, the scrivener, the survey body, the judicial scrivener, and the tax accountant?

Property investigation and sale brokerage are ours (real estate); the application documents to discontinue or alter hazardous-materials facilities go to an administrative scrivener; the soil-contamination survey to a designated survey body; ownership-transfer registration to a judicial scrivener; and tax to a tax accountant. Each is an independent business entity, and you contract with each separately.

From checking the site to conversion and sale, several professionals are involved. Dividing the roles at the outset prevents overlap and gaps.

Who	What they handle
Yotsuba Real Estate Co., Ltd.	Property investigation (history of underground tanks/soil, organizing the use district), brokerage of sales/leases, important-matters explanation
Yotsuba Administrative Scrivener Office (separate contract)	Preparing documents submitted to public offices, such as hazardous-materials facility discontinuation notices and installation-alteration permits
Designated survey body (specialist)	Soil-contamination survey, analysis, and remediation planning
Hazardous-materials / demolition specialist	Removal of residual fuel, removal or in-place safety measures for underground tanks, demolition work
Judicial scrivener	Registration of rights such as ownership transfer
Land/house surveyor	Registration of physical description such as subdivision and land-category change
Tax accountant	Tax on capital gains, capital expenditure, and inheritance
Lawyer	Disputes over soil or buried objects

We and our office, and the various professionals and specialists, are each independent business entities. Where roles overlap, we clarify before the contract who handles what, and you contract with each separately. We neither receive nor pay any referral fee or introduction commission. Consultations are free. For commercial properties, see Investment & commercial real estate; for document-preparation on permits, see Consulting an administrative scrivener.

FAQ

Q. Can a tank remain underground even on a site that looks like cleared land?
A. Yes. At closure, some gas stations do not remove the tank and leave it in place (filling the tank interior with water or sand, etc.). Confirm the current state not by appearance but by the past installation permit, completion-inspection certificate, the copy of the Article 12-6 discontinuation notice, and drawings. A tank left in place can lead to extra cost and procedures during conversion excavation or a buyer's re-survey.

Q. When a gas station closes, does a soil-survey duty always arise?
A. No. A gas station's underground tanks and dispensing equipment generally are not a "specified facility using hazardous substances" under the Water Pollution Prevention Act, so the Article 3 mandatory survey does not begin merely because of closure. In practice, triggers are the Article 4 notification when changing the form of land of 3,000 m² or more (if the governor finds a contamination risk, a survey is ordered under Article 5), local ordinances, and a voluntary survey in the sale. Confirm applicability with the municipality's environmental department and a designated survey body.

Q. I want to make the site a warehouse or shop — can the use district prevent it?
A. Yes. Article 48 of the Building Standards Act and Appended Table 2 set the buildings allowed and the floor-area cap per use district. Warehousing-business warehouses and shops/workshops above a certain size are restricted in residential districts. Gas stations are often on roadsides, so commercial/quasi-industrial districts tend to leave wide options, but confirm individual feasibility at the municipal city-planning / building-guidance desk.

Q. Who bears the tank removal and soil survey costs — seller or buyer?
A. The law does not fix this uniformly; it depends on how the sale contract sets it. Options include handing over as-is (tank left in place) with the buyer bearing it, the seller removing/surveying before handover, or building the cost into the price and apportioning it. Putting the scope of non-conformity liability and the as-is premise in writing is important, and we organize the issues from the brokerage position. For cost estimates, consult a removal/survey specialist.

Sources (primary information)

• e-Gov Law Search "Fire Service Act" (Act No. 186 of 1948; Art. 11(1) = installation/alteration of facilities requires the permit of the municipal mayor etc., Art. 11(5) = may not be used until it passes completion inspection, Art. 12-6(1) = notify the municipal mayor etc. without delay once use is discontinued. Accessed 4 Oct 2026)
• e-Gov Law Search "Order for Enforcement of the Act on the Regulation of Hazardous Materials" (Cabinet Order No. 306 of 1959; Art. 13 = standards for underground tank storage, Art. 17 = standards for dispensing facilities. Accessed 4 Oct 2026)
• Fire and Disaster Management Agency, guidance/notices on "discontinuation of hazardous-materials facilities" (removal of a discontinued tank is the rule; where it must be left in place, fill the interior with water/sand etc.; operated via municipal review standards. Accessed 4 Oct 2026)
• e-Gov Law Search "Soil Contamination Countermeasures Act" (Act No. 53 of 2002; Art. 3 = soil-contamination survey on discontinuing a specified facility using hazardous substances, Art. 4 = notification of changing the form of land of a certain size (3,000 m² in principle) or more, Art. 5 = survey order by the governor. Accessed 4 Oct 2026)
• Ministry of the Environment, "On the enforcement of the Soil Contamination Countermeasures Act" and related guidelines (applicability of a specified facility using hazardous substances; survey by a designated survey body. Accessed 4 Oct 2026)
• e-Gov Law Search "Building Standards Act" (Act No. 201 of 1950; Art. 48 / Appended Table 2 = use restrictions on buildings within use districts. Accessed 4 Oct 2026)

• Whether a gas station's underground tanks/dispensing equipment are a "specified facility using hazardous substances" under the Soil Contamination Countermeasures Act, and which ordinance survey applies, differ by facility configuration and municipality. This article does not assert applicability; the need for a survey is treated as [unverified], assuming confirmation by the municipality's environmental department and a designated survey body.
• The specific measures for removing/leaving underground tanks, and the format and attachments of the discontinuation notice, are operated differently by the fire department with jurisdiction and municipal review standards. Confirm against the Fire and Disaster Management Agency's latest guidance and the municipal standards.
• Removal/survey/remediation costs and capital-gains or capital-expenditure tax vary greatly with circumstances. This article does not assert specific amounts or tax. Get estimates from specialists and consult a tax accountant for tax.
• This article is general information, not an individual legal or tax judgment. Preparing application documents to discontinue/alter hazardous-materials facilities is for an administrative scrivener, the soil-contamination survey for a designated survey body, rights registration for a judicial scrivener, physical-description registration for a land/house surveyor, tax for a tax accountant, and disputes for a lawyer.
• Property investigation, sale brokerage, and the important-matters explanation are handled by Yotsuba Real Estate Co., Ltd. (real estate brokerage); the various professionals and specialists contract with you separately as independent business entities. There is no exchange of referral fees or introduction commissions.

About the author

Joji Uramatsu — Licensed Real Estate Transaction Specialist (Tokyo Governor registration No. 293544) and Administrative Scrivener (registration No. 25087022). Representative Director of Yotsuba Real Estate Co., Ltd. (real estate brokerage, Tokyo Governor (1) No. 113304) / Head of Yotsuba Administrative Scrivener Office. Kohinata, Bunkyo-ku, Tokyo, about 5 minutes' walk from Myogadani Station. For acquiring and converting a former gas station site, the fire-safety procedures for underground tanks, the need for a soil-contamination survey, and the use-district restrictions are checked side by side, and property investigation and referral to each professional are organized. See the author page for the full profile.