How This Differs from Our Earlier Coverage — Restrictions Already in Force by Ordinance, Not Projections

We have previously covered individual disaster layers affecting hotel sites: 71 properties with 711 rooms in sediment-disaster red zones under the Sediment Disaster Prevention Act, river-flood risk and resilience investment for onsen ryokan under projected flood inundation, and a 4.7x difference in pile length for Tokyo Bay hotel sites driven by bearing-stratum depth.

This article covers none of those. It is limited to a separate legal layer: Article 39 of the Building Standards Act and the local ordinances enacted under it. The decisive difference is that a flood inundation zone is predictive information (“the water may reach this height”), whereas a disaster hazard zone is a rule (“you may not build X here”). The former informs design and insurance decisions; the latter directly determines whether a building permit is granted.

One more point. The structural rules in sediment disaster special warning zones apply to “buildings with habitable rooms” regardless of use, while disaster hazard zone ordinances are in many cases written with a use restriction: “buildings used as dwellings.” Whether lodging facilities fall within that use restriction is the subject of this article.

Designated in 615 Municipalities Across 36 Prefectures — Cliffs, Not Tsunamis, Dominate

We scanned the disaster hazard zone data in the MLIT Real Estate Information Library as of September 16, 2026, covering 22,260 tiles at zoom level 11 (latitude 23.8–46.2°N, longitude 122.0–146.5°E). We extracted 22,976 features; after de-duplicating by local government name, they resolve to 615 municipalities in 36 prefectures and 122 ordinances by ordinance name. Note up front that this is not a complete national census but a tally of the zones retrievable within the scan range.

The results ran counter to intuition. Tsunami-type designations, well known from the reconstruction after the Great East Japan Earthquake, cover only 30 municipalities; the overwhelming majority were designations based on steep-slope collapse, landslides and similar hazards (520 municipalities). By prefecture, too, the top ranks go not to tsunami-hit areas but to prefectures with hilly or volcanic terrain: Chiba 43, Kumamoto 41, Kagoshima 36 and Aomori 35. Many of these are not individual municipal ordinances but prefectural building standards ordinances that designate zones across the whole prefecture.

The table below aggregates, from our database, the lodging stock of the municipalities containing zones, by hazard type. The property and room counts here are totals for the entire municipality, not limited to properties located inside a zone. Because zones cover only a small part of each municipality, read these figures as an indicator of how much lodging stock sits in local governments where the ordinance layer needs to be considered.

The practical implication is clear. The stance that disaster hazard zones only need checking when sourcing coastal sites does not hold. Resort sites in hill country, onsen towns on river terraces, redevelopment in urban areas facing slopes — in every one of these, the zone must be checked in the same step as zoning and floor-area ratio.

Reading 8 Ordinances in the Original — Some Cities Expressly Ban Hotel Businesses, Others Say Nothing About Use

This is the core question. Do lodging facilities fall within the statutory limitation “buildings used as dwellings”? From the extracted local governments, we read the original text of eight representative ordinances and organized them by type of restriction and treatment of the hotel business. To state the conclusion first: treatment differs by local government, and one cannot say nationwide either that hotels “can be built” or that they “cannot.”

The clearest type names the hotel business in the text. Article 3(1) of the Iwaki City Ordinance on Disaster Hazard Zones reads:

The hotel business under Article 2(1) of the Hotel Business Act encompasses hotel/ryokan operations, simple lodging (kan’i shukusho) operations and boarding-house operations. In other words, this ordinance prohibits new construction in Class 1 zones regardless of the form of lodging business. Article 3(2) requires that buildings in Class 2 and Class 3 zones “have the structure prescribed by regulation,” so the ordinance switches between prohibition and structural rules in stages according to the zone’s risk level. Furthermore, Article 5 provides that when a building straddles the inside and outside of a zone, Article 3 applies to the entire building, closing off any room to avoid the restriction with a site plan that straddles the zone boundary.

Ishinomaki City follows the same type, but by listing uses. Article 3 of the Ordinance on the Designation of Disaster Hazard Zones and Building Restrictions in Ishinomaki City in Connection with the Great East Japan Earthquake lists the restricted uses as “houses, apartment buildings, dormitories, boarding houses and other buildings with residential rooms, hotels, ryokan, hospitals, clinics with beds and child welfare facilities, etc.” The city’s published materials likewise explain that “buildings used for residence, such as houses, apartments, hotels, minshuku guesthouses, child welfare facilities and medical facilities, cannot be built.”

In the same disaster-hit region, however, there are also ordinances whose text does not touch on lodging use. Article 3 of the Rikuzentakata City Ordinance on Disaster Hazard Zones says only that “within a disaster hazard zone, no person shall construct a building used as a dwelling,” with neither a list of uses nor any reference to the hotel business (Article 4 provides exemptions for temporary structures and for cases the mayor deems unavoidable in light of the surrounding circumstances). The Ofunato City Ordinance on Building Restrictions for Tsunami Disaster Prevention likewise covers “buildings used as dwellings and social welfare facilities, etc.” and does not specify the hotel business.

The third type does not prohibit uses but imposes floor-height and structural requirements regardless of use. In the Nagoya City Coastal Disaster Prevention Zone Building Ordinance (in force since 1961, enacted after the Isewan Typhoon), the list for the construction ban in Article 6 (covering areas within 50 meters of the coastline or riverbank in Class 1 zones that the mayor designates; excluding buildings whose principal structural parts are non-wooden and buildings whose habitable-room floors are at N.P. +5.5 meters or higher) reads “houses, mixed-use houses, apartment buildings, dormitories, boarding houses and other buildings with residential rooms, hospitals and child welfare facilities, etc.” and does not name hotels or ryokan. Article 5 defines a “residential room” as “a room used for residence.” On the other hand, Article 7 sets the first-floor height at N.P. +4 meters or higher (Class 1 zone) or N.P. +1 meter or higher (Class 2–4 zones) depending on zone class, and Article 8 makes non-wooden principal structural parts the rule in Class 1 zones. These do not limit the use.

The Higashimatsushima City Tsunami Disaster Prevention Zone Building Ordinance is also a floor-height/structure type, requiring among other things that the floor of first-floor residential rooms be at least 1.5 meters above the road adjoining the site and that house foundations be reinforced concrete. The Shiga Prefecture Ordinance on the Promotion of Basin Flood Control designates flood alert zones as disaster hazard zones; Article 14 makes “buildings used as dwellings” and “social welfare facilities, etc.” subject to the governor’s permission, and Article 15 sets permit requirements including that the floor of at least one habitable room, or a rooftop usable for evacuation, be at or above the projected water level, and that principal structural parts below the projected water level be reinforced concrete or steel.

The Shizuoka example shows the need to look one regulatory layer over. The prefecture’s materials set three zones side by side and distinguish the buildings they cover: disaster hazard zones (Act Art. 39; prefectural ordinance Arts. 3–4) cover “buildings used as dwellings,” the cliff ordinance (prefectural ordinance Art. 10) covers “all buildings,” and sediment disaster special warning zones cover “buildings with habitable rooms.” Even if a lodging facility slips through the use limitation of the disaster hazard zone, it is certainly caught by the use-agnostic cliff ordinance, and since guest rooms are habitable rooms, it is also subject to the structural rules of sediment disaster special warning zones. The reading “outside Article 39, so it can be built freely” can be negated by an adjacent layer.

The Price of Land Housing Has Left — 32–43% Cheaper at the Same FAR, but Only 3.3% on Total Cost per Room

So how much cheaper does land become when residential use is restricted? Nagoya’s Coastal Disaster Prevention Zone is one of the few cases where the zone is set broadly within the urban area and there are ample land price survey points both inside and outside it. We overlaid the land price survey points (official land price publication and prefectural land price survey, 2025) from the Real Estate Information Library on the zone polygons and compared inside versus outside.

The median residential official land price is ¥116,000/㎡ inside the zone (N=53 points) versus ¥203,000/㎡ outside (N=259 points), a gap of -43%. The key point is that both have a median floor-area ratio of 200% and a median building coverage ratio of 60%. In other words, this price gap is not a difference in how much floor area can be built. Even narrowing the outside sample to southern Nagoya (south of latitude 35.11°N) to bring location conditions closer, the zone is 32% cheaper than the outside figure of ¥170,000/㎡ (N=73 points).

Now convert to a per-room basis. With assumptions stated explicitly, we set two cases: an urban format that uses up the floor-area ratio, and a low-rise format that uses land extensively.

The result suggests not expecting too much from cheap land. In an urban format that uses up the floor-area ratio, even with land 32% cheaper than comparable southern Nagoya, the difference in total cost per room is only ¥1.2M, or 3.3%. At this density land accounts for just 7–10% of total investment and is buried in the range of construction cost variation. For reference, Aichi Prefecture’s estimated realized ADR was about ¥8,600 in August 2026 (N=505 properties); at that rate level, there are few situations where a 3.3% reduction in investment makes or breaks feasibility.

Conversely, for a low-rise format that uses land extensively, the picture changes. In Case B the difference is ¥8.1M per room, or 13.0%, and the land share jumps to 32–41%. Single-story and low-rise resorts, detached-villa layouts, suburban formats with ample parking — in these land-intensive formats, the discount on land caused by restricting residential use starts to matter for investment decisions. As the flip side of the dynamic we covered in Hotel vs Condo Land Rivalry: ADR-Implied Feasible Land Price Map, on land where housing has dropped out as a bidder, the formats that do not chase floor-area ratio capture the price advantage most easily.

How much the land discount matters depends on the combination of discount rate and construction unit cost. Holding the outside-zone land price (southern Nagoya ¥170,000/㎡) and inflation to the construction midpoint (+13.0%) from the assumptions above fixed, we varied the inside-zone land discount and the construction cost per tsubo (2025 actual basis) and recalculated how much total cost per room shrinks (Table 4). In the full-FAR format, even the most favorable combination — a 50% discount and ¥2.0M per tsubo — yields a reduction of only 6.1%. In the low-rise, land-intensive format, even the least favorable combination — a 20% discount and ¥2.8M per tsubo — secures 7.4%. The choice of format moves the result more than any error in estimating the discount.

One more remark on floor-height and structural rules. In Class 1 zones of Nagoya’s Coastal Disaster Prevention Zone, non-wooden principal structural parts are the rule, but lodging facilities are generally planned in reinforced concrete or steel anyway because of Fire Service Act and Building Standards Act requirements. A rule that forces a structural change on a wooden house may impose no substantive additional cost on a lodging use. The required floor-height lift (N.P. +1 meter in Class 2–4 zones) is also easier for a hotel to absorb than for a house, since a hotel has the design freedom to put the lobby and back of house on the first floor. The burden of the rules is asymmetric by use.

Hotels Already Operate Inside the Zones — The Distribution in Nagoya

For the seven coastal cities where the scan retrieved enough polygons (Nagoya, Ofunato, Kamaishi, Kesennuma, Miyako, Natori and Ishinomaki), we overlaid lodging properties from our database by coordinates and found 55 properties with 2,487 rooms inside the zones. Given that the zones cover only a small share of municipal area, this is by no means a small number.

Two caveats apply when reading this distribution. First, the ordinances contain exemptions for buildings that already existed before enforcement (e.g., Iwaki City ordinance Art. 4, Ofunato City ordinance Art. 5(2)), so existing properties inside a zone are not in violation. Second, many ordinances divide zones into Class 1, Class 2 and so on by risk level, and the ban applies only to the highest-risk class. “Inside a zone” does not mean “land that cannot be built on.”

The map below uses Nagoya’s Coastal Disaster Prevention Zone as an example, overlaying the zone polygons and the distribution of lodging properties (10+ rooms). Of 367 properties citywide, 17 properties with 1,275 rooms are inside the zone; property density is higher outside, but a certain amount of lodging stock has clearly established itself inside the zone as well.

Five Points to Confirm in Due Diligence

Finally, here is the order in which to work through these points in site acquisition and collateral valuation.

Disaster hazard zones are a system that removes land from the housing market. Whether lodging use can enter depends not on the text of Article 39 but on a single line in the ordinance each local government has written. As long as there are ordinances like Iwaki’s that explicitly cite the Hotel Business Act, the generalization that “a hotel is not a dwelling, so it can be built” does not hold. Conversely, there are ordinances like Nagoya’s that leave lodging facilities out of the list of banned uses and impose only floor-height and structural requirements. Read the text, make the inquiry, confirm it in writing — building this obvious procedure into the process with the same weight as checking land prices and floor-area ratios is the practical answer to this regulatory layer.