Legal and Hydrogeological Requirements for Construction in the Czech Republic

Groundwater has become a critical factor determining the feasibility, technical solutions, and overall costs of construction projects in the Czech Republic. If you are designing a project without a deep understanding of hydrogeology, you risk significant complications during the permitting process and future legal disputes. In this article, our Prague-based attorneys explain how ARROWS helps clients navigate new assessment standards and ensure a smooth approval process under Czech law.

Quick Summary

• Groundwater impact assessment is an essential part of project preparation in the Czech Republic. Construction projects can affect the level, quality, and regime of groundwater, which is regulated by the Czech Water Act, the Building Act, and the Environmental Impact Assessment Act.
• Hydrogeological surveys are mandatory for relevant projects. Without one, it is impossible to obtain a project permit, especially if the construction includes underground floors, infiltration systems, drainage, or may affect water bodies.
• Ignoring hydrogeological conditions leads to sanctions, project rejection, or costly repairs. Developers often make the mistake of insufficiently assessing the impact on surrounding hydrogeological conditions and the stability of neighboring properties.
• Attorneys from the ARROWS law firm in Prague regularly handle the entire procedural framework, from preparation through permitting to representation in disputes. We have experience with hundreds of clients from among development and construction companies.

Groundwater as a critical element for construction

For a long time, groundwater was viewed as a marginal factor in structural design, handled by engineers and not considered a significant legal issue. Today, the reality is different, as groundwater affects the safety of the building, its technical solution, costs, and especially the procedural possibilities of its permitting. Buildings in low-lying areas can divert or dam water, which changes the water level regime in the wider surrounding area.

Czech building authorities and concerned bodies now require risks to be clearly identified and addressed as early as the project preparation phase. This approach requires a comprehensive hydrogeological assessment—a systematic evaluation of how a specific construction will affect the hydrological balance of the area. This is not just paperwork; it is a factual mapping of risks that could lead to long-term disputes with neighbors and legal sanctions.

What has changed in the assessment approach

Legislation in the Czech Republic places increasing emphasis on the protection of water bodies. A key change lies in the inseparability of the construction impact assessment from the permitting process under the new Czech Building Act. Developers now face requirements for hydrogeological reports that must contain specific data on groundwater levels and predictions of changes after construction is completed.

In practice, relying on research from archival boreholes is often insufficient; groundwater level measurements must be performed and evaluated under various climatic conditions. Water quality is also assessed, particularly its aggressiveness toward concrete structures and the risk of spreading contamination. Clients of ARROWS resolve this process in cooperation with authorized hydrogeologists, ensuring that documentation for the authorities is legally robust.

Legislative framework for impact assessment

The legal framework for groundwater protection in the Czech Republic is complex and primarily governed by Act No. 254/2001 Coll., on Water (the Water Act). Also crucial is the new Act No. 283/2021 Coll., the Building Act, which integrates construction permitting processes, and Act No. 148/2023 Coll., on the Unified Environmental Statement (JES). For large-scale projects, the EIA Act is also relevant.

Technical procedures rely on geotechnical survey standards that define methods for site investigation. Navigating this legislation is not simple, as the laws are interconnected and contain specifics for different types of projects. Investors utilize legal counsel to prevent situations where an authority suspends proceedings due to insufficient hydrogeological documentation.

Environmental Impact Assessment Act (EIA)

The Czech EIA Act (100/2001 Coll.) is essential for constructions that may have a significant impact on the environment, such as large development complexes or industrial buildings. The annex to the Act lists categories of projects where the EIA process is mandatory or subject to a screening procedure. Documentation must then include a detailed chapter on groundwater impacts.

In practice, you must demonstrate whether the construction will affect the groundwater level, whether there is a risk of deteriorating the chemical status of the water body, or changes in flow. This assessment must be supported by survey data and modeling; otherwise, the relevant authority will not issue a positive statement. Our Prague-based attorneys assist clients particularly in settling comments from the public and concerned authorities.

The Water Act and the permitting process

The Czech Water Act (254/2001 Coll.) regulates water management, with Section 8 being key for construction as it defines activities requiring a permit. If a construction requires pumping groundwater to lower the level in a construction pit or the infiltration of rainwater, you need a permit from the water management authority. This is now often part of an integrated decision.

In practice, this means that permanent drainage or infiltration systems are forms of water management that the water management authority may restrict or reject. It is vital that no more water is extracted from the area than the hydrological balance allows; otherwise, the permit will not be granted.

These are the situations that our Czech legal team at ARROWS resolves by seeking alternative technical solutions in cooperation with designers and subsequently negotiating with the authorities.

microFAQ – Legislative requirements for groundwater assessment

1. Do I need a hydrogeological report for every construction?
Not for every project, but for constructions involving infiltration, underground floors extending into the aquifer, or for wells, a report or statement from a hydrogeologist is essential. Specific requirements will emerge from consultations with the building authority or within the JES framework.

2. Who prepares the hydrogeological report?
Only a person with professional competence in the field of hydrogeology according to the Czech Act on Geological Works. Without the official stamp of an authorized geologist, the report is not a relevant document for the authorities.

3. How long does it take to prepare the documentation?
The survey itself typically takes weeks to months depending on complexity and monitoring needs. Our attorneys in Prague help coordinate the process to avoid unnecessary delays in the project schedule.

How construction affects groundwater

Constructions interact with water through a barrier effect, where foundations create an obstacle to natural flow. If underground floors extend into the aquifer, water levels rise on the inflow side. This often leads to waterlogging of neighboring buildings, excessive pressure on insulation, and the risk of serious structural defects.

The second phenomenon is the drainage effect, where a system for permanent drainage of the foundation joint locally lowers the groundwater level. This creates a so-called depression cone, which can cause nearby wells to dry up or lead to ground subsidence. Unstable subsoil then threatens the overall stability of surrounding buildings and utility networks in the wider area of the Czech Republic.

The third risk is contamination, which occurs through the leakage of petroleum substances or sewage during construction and operation. Impurities spread through the flow and can degrade drinking water sources over a wide area. For the investor, this establishes direct liability for environmental damage and compensation for all incurred losses under applicable Czech water management regulations.

Mgr. Karel Huneš

associate

• hunes@arws.cz

JUDr. Tereza Snopková, Ph.D.

associate

• snopkova@arws.cz

The Drainage Effect of Structures and Drainage Systems

Drainage systems are a standard solution for protecting substructures, but their impact on the surroundings is often underestimated. If you divert water away from your building, you change the hydraulic conditions in the wider area, as the drainage acts like a well drawing water toward itself.

In such cases, our attorneys in Prague at ARROWS handle liability relationships, negotiations with insurance companies, and the setting up of out-of-court settlements. Hydrogeologists point out that the deeper the drainage is placed, the wider its reach. 

Drainage at a depth of several meters can affect the water level at a distance of tens to hundreds of meters, which in practice can lead to the drying out of the subsoil under neighboring houses and their subsequent settlement in the Czech Republic.

Water Level Rise and Its Impact on Surrounding Structures

The opposite problem is the rise of the water level in front of an underground wall, where the structure "dams" the underground flow and the water rises. For buildings in flood zones or floodplains, the combination of rising groundwater and a flood situation can lead to the flooding of neighbors' basements.

The correct procedure requires a hydrogeological model proving that the proposed technical solution ensures the water level will not rise above a critical limit. Without this assessment, the construction becomes a source of conflict and a risk for the investor, who may face litigation in Czech courts.

Hydrogeological Survey as a Foundation

A hydrogeological survey is an essential basis for project documentation and includes fieldwork, laboratory analysis, and evaluation. The goal is to determine the groundwater level, flow direction, rock permeability, and water chemistry.

The data obtained answers questions regarding the steady water level, its fluctuations throughout the year, and its aggressiveness toward concrete. Without this data, the designer is "guessing," and the investor risks additional costs for foundation changes during construction, which often lead to disputes with the contractor under Czech commercial law.

microFAQ – Risks and Liability

1. Am I liable if a neighbor's house settles because of my drainage?
Yes, if a causal link is proven between your construction and the damage incurred. Liability is both objective and subjective depending on the specific situation. Our Prague-based attorneys can help you evaluate the level of risk and set up a defense.

2. Can I get insurance for potential disputes?
Yes, builders and developers in the Czech Republic use liability insurance that also covers damage caused to surrounding real estate. However, it is necessary to check exclusions regarding subsoil settlement. ARROWS will help you review the insurance terms and conditions.

3. How high can the compensation for damages be?
It depends on the actual damage, ranging from the costs of repairing cracks (hundreds of thousands of CZK) to the structural stabilization of buildings (millions of CZK). Legal prevention is always cheaper than subsequent litigation in Czech courts.

What a Hydrogeological Report Must Contain

To be usable for Czech authorities, the report must contain:

1. Characteristics of natural conditions – the geological and hydrogeological structure of the site.
2. Groundwater level (GWL) measurement results – data on the encountered and steady levels, ideally including seasonal fluctuation data.
3. Aquifer parameters – filtration coefficient, flow direction.
4. Water chemistry – water aggressiveness (e.g., sulfate aggressiveness) affecting the choice of concrete.
5. Assessment of the project's impact – prediction of water level influence (rise, fall), impact on surrounding sources (wells), and proposed measures.
6. Conclusion with recommendations – clear determination of conditions for foundations and water management.

This document is key evidence in any potential future disputes.

microFAQ – Process and Content of a Hydrogeological Survey

1. How long does the survey take?
The work and evaluation usually take 3 to 6 weeks, or longer for more complex monitoring. Our Czech legal team will help you include these deadlines in your contract schedules.

2. Who is responsible for the report?
A responsible evaluator with the appropriate Czech authorization. If the report is incorrect and damage occurs, compensation can be claimed from the processor (or from their insurance).

3. What is the price of the survey?
It ranges from tens of thousands of CZK for family houses to hundreds of thousands for large developments. However, it is a fraction of the cost compared to the risk of remediating a faulty foundation.

Construction Proceedings and Permitting Regarding Groundwater

With the introduction of the new Czech Building Act (No. 283/2021 Coll.), agendas are being integrated, and the process begins with securing a hydrogeological report and project documentation. This is followed by obtaining a Unified Environmental Opinion (JES) for projects requiring opinions under specific environmental laws.

The building authority subsequently issues a project permit under Czech law, which may also include a water management permit, and a system functionality check is conducted upon completion of the construction. Our Prague-based attorneys at ARROWS assist clients in navigating this process to ensure no procedural defects or delays occur.

Conclusion

The impact of construction on groundwater is a critical point in modern construction in the Czech Republic, where ignoring hydrogeology represents a legal hazard leading to construction halts or sanctions. Czech water management authorities and neighbors are highly vigilant today, and legislation is often on their side.

The experience of our Prague-based law firm, ARROWS, shows that investing in quality preparation and legal risk management pays off many times over in the smoothness of the permitting process and construction safety.

Our Czech legal team at ARROWS routinely handles these matters for developers, construction companies, and individual investors. We have experience with hundreds of clients in the construction sector, and our firm carries professional liability insurance in the hundreds of millions of Czech crowns. If you are planning a project in challenging conditions or dealing with a water-related dispute, contact ARROWS law firm in Prague.

FAQ – Frequently Asked Legal Questions Regarding Construction Impact on Groundwater

1. Can I build on a plot with a high groundwater table without an expert report?
Formally, this might pass for some minor structures, but it is an extreme risk. If the construction "floods" or damages a neighbor, you bear full responsibility. The building authority usually requires a report if there is a known risk in the area. We always recommend at least a consultation. Write to us at office@arws.cz.

2. Am I liable for the loss of water in a neighbor's well?
Yes, if your construction demonstrably changed the hydrogeological conditions resulting in water loss ("water diversion"). The burden of proof and expert assessment are key. ARROWS can help you analyze the situation under Czech law.

3. How much does legal assistance in this matter cost?
The price depends on the complexity of the case (contract consultation vs. representation in Czech court litigation). We will be happy to prepare a non-binding quote for you. Write to us at office@arws.cz.

4. What should I do if the authority rejected the project due to water issues?
It is necessary to analyze the reasons for rejection. Often, the project can be modified (technical solutions, infiltration, retention) or the argumentation can be supplemented for an appeal. We will help you find a way forward.

5. Can the authority order the removal of a building due to its impact on water?
Theoretically yes, if the building was constructed in violation of the permit and cannot be retroactively permitted, or if it causes serious damage that cannot be otherwise remedied. In practice, remedial measures (remediation pumping, additional insulation) are usually sought.

6. How can I defend myself against a neighbor's construction?
You must file qualified objections during the project permitting proceedings, ideally supported by your own expert opinion. Passivity does not pay off. Our Prague-based attorneys will represent you in the proceedings.

Disclaimer: The information contained in this article is for general informational purposes only and serves as a basic guide to the issue. Although we ensure maximum accuracy of the content, legal regulations and their interpretation evolve over time. To verify the current wording of regulations and their application to your specific situation, it is essential to contact ARROWS law firm directly (office@arws.cz). We bear no responsibility for any damages or complications arising from the independent use of information from this article without our prior individual legal consultation. Every case requires a tailor-made solution.

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