An inundation area (inundačné územie) is land beside a Slovak watercourse that is normally flooded when water leaves the channel, and it is the one flood zone in which Act 7/2010 bans most buildings. Its edge is the flood line of a 100-year flood or a protection line built for that flow, and the district office fixes it by decree. A flood hazard map only warns, while the area is the legal category.
What an inundation area is in Slovak law
Act 7/2010 on flood protection, in the text in force since 1 April 2025, defines the term in section 20(1). It is land next to a watercourse that is normally flooded by water spilled from the channel. Seen from the channel outwards, the edge is set by one of two things. The first is a flood line, where the water surface of a flood meets the ground. It is either calculated for a flood with a medium probability, whose peak flow is reached or exceeded on average once in 100 years, or surveyed during a flood that the Slovak Hydrometeorological Institute rated as recurring less often than once in 50 years. The second is a linear structure built to protect against floods, if it protects against the 100-year flow.
For a watercourse without embankments, the administrator of significant watercourses prepares a proposal and the district office fixes the extent by decree, under section 20(2). The administrator, in practice the Slovak Water Management Enterprise, also keeps the record of the area and proposes changes (section 20(4)). Section 20(3) lets the extent grow where buildings, objects or camps of the kinds banned in the area already stand between the protection line and the flood line of the 100-year flood.
What may not be placed there
Section 20(5) lists what is forbidden. It starts with residential buildings, and then non-residential buildings. The only exception is accommodation for short stays, and only if it does not worsen the run-off of surface water, the movement of ice or water quality, resists water pressure and is protected against water entering the interior. Warehouses, halls and offices are non-residential buildings and are not covered by it.
The list continues with structures that may worsen run-off, ice movement or water quality, and with material and objects that could do so or that a flood could carry away. It also covers structures that contain harmful or particularly harmful substances, filling stations, tailings ponds, waste dumps, vehicle-dismantling sites and, as a catch-all, any structure a flood could damage or wash away.
Section 20(6) adds acts instead of objects. It forbids fences, hedges and similar obstacles that worsen drainage, digging of soil, sand, gravel or minerals without a permit, and earthworks that may worsen run-off. Farming and forestry in a way that hinders run-off is also banned, as are camps and temporary accommodation, except brief tourist camping.
What may be permitted, and what applies without a decree
Section 20(7) lists what can be allowed: flood prevention measures, water structures other than tailings ponds, structures to take or discharge surface water, hydropower plants and measuring stations. It also names transport structures and pylons that do not worsen run-off or water quality, and temporary structures that do not worsen it. Where earthworks or nature protection measures are unavoidable and could worsen run-off, section 20(8) requires measures that compensate for the harm at the same time.
A missing decree does not lift the test. Under section 20(9), on a site beside an unembanked watercourse where no area is fixed or no hazard map exists, a proposal to place a structure, or a request for an activity banned in the area, is judged against the probable flood line of a 100-year flood or the line of the largest flood known so far. Section 21 adds land with retention potential. A flood protection authority or a municipality may declare it a flood area for flattening the flood wave, and the bans of section 20(5) and (6) then apply the same way. Section 21(2) allows expropriation or a restriction of ownership where a protection structure cannot be built on another person’s land.
Duties of owners, tenants and users
Section 37 binds the owner, the administrator and the user of a structure in the area alike, so a landlord and a tenant are both addressed. Before a flood they must draw up and update a flood plan for securing works, provide staff and equipment, and allow the flood inspection under section 13. They must also show the building decision or occupancy certificate on request and avoid anything that worsens run-off or water quality. Section 10(2) names the same group as authors of that plan.
During a flood they report to the municipality, the flood protection authority and the watercourse administrator, remove objects that worsen run-off and take part in the warning system. From the third degree of flood activity a patrol service is compulsory (section 16(4)). Afterwards they clear the consequences, assess the damage and report to the municipality. A business whose building a flood could reach also needs a rescue plan under a municipal ordinance (section 37(3)).
Fines, limits and who pays for the damage
Section 46(1) sets fines imposed by the district office. Breaking the bans of section 20(5) and (6) costs a company or a sole trader EUR 25,000 to EUR 35,000. Breaching the duties of section 37 costs EUR 7,500 to EUR 35,000, and blocking a flood inspection ordered by the authority costs EUR 7,500 to EUR 17,000. The office must act within one year of learning of the breach and within three years of the breach itself. A repeat within two years can bring up to twice the upper limit.
Public bodies do not stand behind the owner. Under section 2(8) the state, the municipality and the watercourse administrator are not liable for flood damage, except for damage caused directly by flood works. Section 6(4) adds that a real flood reaching past the mapped line gives no claim to compensation. The loss stays with the owner and the user, which is why the area matters to lenders, insurers and lease drafting alike.
Frequently Asked Questions
Is a flood hazard map the same as an inundation area?
No. The map under section 6 shows floods that recur once in 10, 100 and 1,000 years, and it is only indicative. A flood map is only a warning; the legal ban sits with the area itself, which the district office fixes by decree or which the 100-year line defines. Our blog post on Slovak flood rules shows why a flood map only warns while the Act bans.
Can a warehouse be built in the area?
As a rule no. A warehouse is a non-residential building and section 20(5) bans it. The exception covers only short-stay accommodation with protection against flooding. Transport structures, pylons and temporary structures can be allowed under section 20(7) if they do not worsen run-off.
What if the land has no decree?
The test still applies. Section 20(9) judges a proposal against the probable 100-year flood line or the largest known flood. A buyer or tenant should therefore ask the district office, the municipality and the river administrator, and not rely on the absence of a decree.
Do tenants carry the duties too?
Yes. Section 37 names the owner, the administrator and the user together, and the act does not divide the duties between them. A lease should say who prepares the flood plan, who gives access for inspections and who insures the stock.
Looking at a hall or a plot near a river in Slovakia? Send us the address and we will check it against the flood maps and the district office’s decree with you.