Operation of Water Supply Systems in the Czech Republic—Risk Analysis

: A reliable supply of quality drinking water is a fundamental prerequisite for a healthy society and its economic development. Public ownership of water infrastructure is prevalent in most European countries. In the Czech Republic, however, water infrastructure is highly fragmented, which entails multiple risks. The fragmentation of the sector leads to a low economic efﬁciency of operations, the unstable quality of service provision, and signiﬁcant price differences. The aim of the paper is to use the IFE matrix to analyze the strengths and weaknesses of different ways of operating water supply systems in the Czech Republic. Furthermore, through the FMEA method (failure mode and effects analysis), this paper tries to identify the risks and threats to drinking water supplies for selected operators (representing the most frequently used operating models) and, subsequently, it proposes measures to mitigate the identiﬁed risks. The topic was addressed in the form of a case study of selected water system operators in the Czech Republic, and the ﬁndings indicate the compartmentalized model to be the most appropriate operating model.


Introduction
As declared by the European federation of national associations of water services (EurEau): "apart from the general cases of England and Wales and specific cases in the Czech Republic, the ownership of water infrastructure across Europe is public" [1].On the contrary, the water infrastructure in the Czech Republic is highly fragmented.In 2022, there were over 7000 owners and more than 3000 operators of water systems in the Czech Republic [2] and such a high degree of fragmentation entails many risks.The topic was also addressed at the "Water Supply and Sewerage Operations 2019" conference, where it was declared that 75% of the market is currently failing to meet legal obligations to renew its networks.The risks of the fragmentation of the water sector were then similarly assessed at the "Financing Water Infrastructure" conference held in February 2020 [3].According to the State Health Institute (SZU), the quality of drinking water in the large water supply systems in the Czech Republic is similar to the European average, but the quality of drinking water from the smaller water supply systems, often operated by local operators or owners, is much worse and falls below the European average [4].According to Act No. 274/2001 Coll., on Water Supply and Sewerage, the owner of a water management infrastructure in the Czech Republic is obliged to ensure its smooth and safe operation [5].This service may be provided by the operator itself or upon an infrastructure operating agreement concluded with the operator.The scope of the various activities to be provided by the owner or the operator may be defined within a specific contract between the two parties.

Models of Operating Water Supply Systems in the Czech Republic
According to Rektořík and Hlaváč, the basic models of ownership and operation can be divided into two groups-mixed ownership and separate ownership models [6].EurEau states that delegated private management (referred to as the compartmentalized operating model, belonging to the separate ownership models group), in which a responsible public entity entrusts a private company to operate the water services based on a rental, lease or a concession agreement, is prevailing in the Czech Republic (59% of the market) [1].Even the methodology of the State Environmental Fund (SEF) lists this model of operation as the most common model in the Czech Republic [7].The principle of this model stems from the participation of two entities, where one entity is public and owns the infrastructure and the other entity is an operator and is private.
The group of mixed ownership operating models comprises the ownership operating model, the independent model, and the mixed operating model.The ownership operating model, in which the operator is established and 100% owned by a public owner(s) of the operated infrastructure, is the least frequently used operating model in the Czech Republic.Unlike the compartmentalized operating model, a municipality owns and controls the operating company which may be either purpose-built commercial companies or technical services of a city.
An independent model, where a municipality operates the infrastructure itself, on its own behalf and under its own responsibility, and which is predominantly used by smaller municipalities, is another possibility [7].Should the municipality itself be the owner of the water infrastructure, it is subject to the rights and obligations determined in Sections 7 and 8 of Act 274/2001 Coll.(Water Supply and Sewerage Act) [5].The basic obligation under the Act is to "ensure smooth and safe operation of water supply and sewerage systems, to establish financial reserves for their renewal and to document their use for these purposes".Some specialized activities can be outsourced by municipalities under a service agreement.However, due to the very extensive and complex legislation in this area and the financial constraints, municipalities often conclude operating agreements with private operators to whom they transfer part of their responsibilities and risks.
Another model used quite often in practice is the so-called mixed operating model, where the entity is both the owner and the operator (the owner and the operator of the infrastructure are the same entity, different from the municipality-for example, municipalities invest their assets in a company which then becomes both the owner of the infrastructure and the operator) [7].
An overview of the possible operating models in the Czech Republic is depicted in Table 1.A significant proportion of the total number of operators (more than 7000 in the Czech Republic) is represented by small municipalities supplying water to less than 1000 inhabitants.However, the 50 largest operators supply around 90% of the citizens with drinking water.Among the top 50 operators according to the amount of invoiced drinking water, the compartmentalized operating model is utilized by 68% of operators and the mixed operating model by 26% of operators [8].The IFE matrix is used to evaluate the strengths and weaknesses of the most frequently used models of operating water supply systems in the Czech Republic.Using this matrix may help municipalities in deciding which operating model best suits their needs.
Risk analysis using the FMEA method was performed for selected operators representing the most frequently used operating models, determining which operating model is most appropriate in terms of risk resilience.

Safety and Availability of Drinking Water Supply
The World Health Organization (WHO) Guidelines for drinking water quality recommend the development of water safety plans (WSPs) as the most effective means of ensuring the consistent safety and availability of drinking water supplies.WSPs are based on a comprehensive approach to assessment and risk management throughout the drinking water supply chain [9].In the European region, this approach is increasingly accepted by water supply companies developing their own risk analyses.The process of risk assessment in the production and distribution of drinking water (the Czech equivalent of the globally used water safety plan) was implemented into Czech legislation through the amendment to Act 258/2000 Coll. on the Protection of Public Health, which came into force on 1 November 2017 [10,11].Within six years of the Act's entry into force (i.e., by 1 November 2023), drinking water suppliers were obliged to prepare a risk analysis and reflect its conclusions in their operating regulations.However, many mistakes (i.e., inadequate expertise, imperfect knowledge of the system assessed, and lack of field surveys) can be made in the risk analysis itself, consequently devaluing the whole process.Risks must not only be correctly identified (including field investigations) but also correctly assessed.Different methods can be used for risk assessment; however, it is essential that the method used provides results in a form that will present the character of the risk and how to address it [12].Proposed measures to reduce or eliminate risks must then be realistic and achievable.A properly conducted risk assessment and the implementation of the proposed measures can contribute to improving water quality, the better protection of water resources, better monitoring, and a reduction in the number of failures of the water supply system, as well as a reduction in operational costs for the implementation of the corrective measures and improvement of the health status of drinking water users.For small operators and contractors in particular, risk assessments can be difficult to comprehend, for example due to their lack of expertise.The aim of this article is, among other things, to provide owners and operators with guidance on how to proceed with the risk analysis of water system operations.

Materials and Methods
The strengths and weaknesses of the most frequently used operating models of water supply systems in the Czech Republic were evaluated using the IFE (internal factors evaluation) matrix [13].The IFE matrix is a tool to reveal a company's strengths as well as weaknesses.It is recommended that the matrix be symmetrical, i.e., it includes an equal number of strengths and weaknesses.Each factor should be assigned a weight ranging from 0.00 (low importance) to 1.0 (high importance).The sum of the weights of the strengths and weaknesses must equal one.In addition, each factor must be assigned a 1 to 4 rating to indicate the level of weakness and strength: 4-significant strength, 3-less significant strength, 2-less significant weakness, and 1-significant weakness.By multiplying the weight and the rating, we obtain an overall weighted score on the basis of which the final assessment is performed.The weighted score is simply the sum of all individual scores, with the best possible score being 4.00, while the worst possible score is 1.00.
Risk analysis methods used in water supply systems are discussed, for example, in the study by Kombo Mpindou et al. [14].In our study, we decided to use the FMEA method for risk analysis, as FMEA (failure mode and effect analysis) is one of the most widely used methods of expert analysis [12,14].It is a structured reliability analysis, identifying potential system failures and their causes and consequences.The FMEA method is considered an effective risk analysis method allowing us to recognize potential failures at different stages and to determine possible consequences to evaluate the risks and ways of prevention.It also serves as an early warning method.The expert group selected representatives representing different operating models for which the FMEA risk analysis was performed.
The level of risk was rated on a scale of 1 (Insignificant risk) to 5 (Critical risk) according to the severity of the consequence of the risk (Table 2).The probability of the risk incidence (Table 3) was rated on a scale of 1 (Unlikely) to 5 (Very high).The ability of detection (Table 4) was also rated on a five-point scale of 1 (Almost certainly detectable) to 5 (Absolute uncertainty).The risk priority number (RPN) index was determined as the multiplication of the significance, incidence, and probability of risk.

Critical
Very high severity threatening the entire process with critical consequences for end users, significant threats to water quality or taking the entire system out of service.

Very high
The probability of the risk is very high, measures must be implemented immediately.

Absolute uncertainty
The risk is unpredictable 5

Low
The risk is hard to predict 4

Moderate
The probability of risk detection is hard to predict. 3 High High probability of risk detection, there are standard procedures in place to monitor and detect risk. 2 Almost certain Very high probability of detecting the risk using standard control mechanisms. 1 A flowchart of the proposed FMEA model is illustrated in Figure 1.For all identified risks, both existing precautions and proposed risk reduction measures were listed.
For the purpose of the analysis, the entire water supply system was divided into three areas (water source, water treatment, and distribution system) and the risks were assessed for each area separately.As concerns water sources, the operator may have very limited possibilities to manage risks, e.g., in the case of surface water sources, which should be taken into consideration.Connections and domestic distribution systems owned by the owners of the connected properties are not addressed in this analysis as the operator has very limited possibilities to influence these potential risks.The risk analysis was carried out by a four-member expert group.The composition of the expert group was based on the skills of the individual members, with each expert s decision given equal weight.Input information on the topic was obtained through desk research and additional information was drawn from internal sources provided by the selected water system operators.For all identified risks, both existing precautions and proposed risk reduction measures were listed.
For the purpose of the analysis, the entire water supply system was divided into three areas (water source, water treatment, and distribution system) and the risks were assessed for each area separately.As concerns water sources, the operator may have very limited possibilities to manage risks, e.g., in the case of surface water sources, which should be taken into consideration.Connections and domestic distribution systems owned by the owners of the connected properties are not addressed in this analysis as the operator has very limited possibilities to influence these potential risks.The risk analysis was carried out by a four-member expert group.The composition of the expert group was based on the skills of the individual members, with each expert's decision given equal weight.Input information on the topic was obtained through desk research and additional information was drawn from internal sources provided by the selected water system operators.

Analysis of Strengths and Weaknesses of Individual Operating Models of Water Supply Systems in the Czech Republic
The individual models of operating water supply systems in the Czech Republic, described in the introduction chapter, obviously have their advantages and disadvantages.The analysis of the strengths and weaknesses of the different operating models from the municipality's point of view was prepared using the IFE matrix.The municipal perspectives were chosen deliberately, as the owners of water infrastructure in the Czech Republic are usually cities and municipalities or associations of municipalities.

Analysis of Strengths and Weaknesses of the Independent Operating Model
The identified strengths and weaknesses of the independent operating model are illustrated in Table 5.

Factor
Weight (W) The municipality collects water and sewerage charges on its own account 0.05 3 0.15

2.
Supervision is carried out by the municipality 0.07 3 0.21

3.
The municipality itself manages/coordinates the services of external contractors 0.07 3 0.21

4.
The municipality sets its own price for water and sewerage-it can also subsidise from its own resources 0.15 4 0.6

5.
A political tool for municipal leaders to reach voters 0.05 4 0.2

1.
High technical complexity (multiple risks are not treated by the municipality) 0.18 1 0.18

2.
Risk associated with the collection of water and sewerage charges-debt recovery, etc. 0.05 2 0.1

5.
Lack of expert personnel 0.18 1 0.18 The matrix implies that, on the one hand, the most significant strength of this operating model is that a municipality determines its own water and sewerage prices, which may also be subsidized from its own resources.This obviously also serves as a tool for municipal leaders to reach out to the electorate.On the other hand, the most important weakness is high technical complexity and, as the municipality usually does not have qualified experts with the necessary knowledge and experience, many risks are not covered.Although each owner must meet the qualification requirements determined by law (or if they do not meet this condition, they must have an expert representative), in small municipalities, an authorized person usually acts as an expert representative for several municipalities (sometimes dozens of municipalities) and sometimes the job is performed solely as a matter of formality.In addition (as Paul, Kožíšek, and Hloušek also mention), expert representatives are often persons who meet the criteria only as a formality and their practical knowledge of the field is none [11].Other weaknesses include the lack of investment and financial resources for network renovation and maintenance.

Analysis of Strengths and Weaknesses of the Mixed Operating Model
The identified strengths and weaknesses of the mixed operating model are illustrated in Table 6.Table 6.Analysis of strengths and weaknesses of the mixed model of operation (own source).

Factor
Weight (W) The company (VaK) is responsible for the collection of water and sewerage charges-it also bears the risks associated with their collection 0.05 3 0.15

2.
The company finances repairs and maintenance from its own resources 0.08 4 0.32

3.
The company has all the obligations of the owner and is responsible for the operation and for compliance with legislative obligations 0.09 4 0.36

4.
The company has an established control system and risk management system 0.09 4 0.36

6.
The municipality does not incur the costs of equipment, the existence of its own operating entity 0.08 3 0.24

1.
The municipality (association of municipalities) loses the possibility of independent decision-making on the restoration and development of water management infrastructure 0.05 2 0.1

2.
The municipality itself no longer decides on the price of water and sewerage charges, the principle of price solidarity can be applied 0.05 2 0.1

3.
The municipality does not have full control over the quality of services provided 0.12 1 0.12

4.
Operators cannot benefit from the synergies of large providers 0.12 1 0.12

5.
Lack of operator motivation to improve services 0.1 1 0.1

6.
High financial requirements (insufficient depreciation recovery function) 0.07 1 0.07 The matrix shows that the most notable strength of this model is sufficient professional support.Other significant strengths are that the company has a control and risk management system in place.The expert staff and the fact that the company finances repairs and maintenance from its own resources are also significant strengths of this operating model.On the other hand, major weaknesses include the fact that the municipality does not have full control over the quality of the services provided and that operators cannot benefit from the synergies of large providers.The municipality also no longer determines the price of its water and sewerage charges.

Analysis of Strengths and Weaknesses of the Compartmentalized Operating Model
The identified strengths and weaknesses of the compartmentalized operating model are depicted in Table 7.  Sufficient expert personnel 0.1 4 0.4 2.
An economically strong operator can achieve significant savings in operating costs (e.g., bulk discounts on the purchase of materials, energy, etc.) 0.12 4 0.48

3.
The operator brings its own global know-how, established control system and risk management system 0.2 4 0.8

4.
With a properly concluded contract, the municipality does not lose control 0.08 3 0.24

5.
All risks are borne by the operator, the rent is fixed for one year in advance 0.08 4 0.32

1.
Early termination of the contract is difficult 0.1 1 0.1

2.
Profit from the operation goes to the operator, the municipality loses part of the funds in the form of profit 0.1 1 0.1

3.
As the end of the contract approaches, the operator is not sufficiently motivated to treat water management infrastructure in a sustainable manner 0.04 2 0.08

4.
Complex legal processes for the preparation and implementation of the contract procedure 0.1 1 0.1

5.
Possible non-cooperation upon termination of the contract (in case of disagreement)-the operator could take away key experts and information 0.08 1 0.08 The matrix shows that the strengths of this operating model are significantly more prevalent.The most notable strengths include the fact that the operator brings global knowhow, has established control processes, an implemented risk management system, and can benefit from synergies.Another important strength is that an economically strong operator can achieve significant savings in operating costs and has sufficient expert staff.On the other hand, the most important weaknesses are the complex legal processes of preparing and implementing the contract procedure and the difficulty of the early termination of the contract.Another important weakness identified is that the profit from the operation goes to the operator and the municipality loses part of the funds it would have gained by operating the system itself.

Risk Analysis
Risk analysis using the FMEA method was performed for three selected operators of water supply systems in the Czech Republic.These operators were selected by a group of experts as representatives of the respective operating models.A municipality in the Central Bohemian Region, which is the owner of the water infrastructure and is responsible for the safe, continuous, and reliable operation of the system (hereinafter referred to as Operator A), was selected as a representative of the independent operating model.It supplies water to approximately 1100 inhabitants.A company operating water infrastructure also in the Central Bohemian Region was selected as a representative of the mixed operating model.It was founded in 1993 and supplies drinking water to about 65,000 inhabitants (hereinafter referred to as Operator B).A large operator, also in the Central Bohemian Region, belonging to a multinational company and supplying water to approximately 300,000 inhabitants (hereinafter referred to as Operator C), was selected by the expert group as a representative of the compartmentalized operating model.Risks were assessed in three areas-water source, water treatment, and distribution.For all identified risks, existing precautions as well as recommended risk mitigation measures were listed.The FMEA was designed to be universally applicable to operators regardless of their operating model and to enable them to assess risks in respective areas.The analysis itself was carried out by a four-member expert group.

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Water sources The results of the risk analysis for each operator's water source are presented in Tables 8-10 and only the risks with an RPN of 20 or higher are shown.The results of the full FMEA method for the water sources area for all operators assessed are presented in Supplementary Material File S1.In terms of water sources, possible contamination of the source through the increased concentrations of chemicals and their compounds, contamination of the source by synthetic pharmaceuticals and phytopharmaceuticals, and contamination of the source or lack of water caused by natural events such as floods or droughts were assessed as the most significant risks.A possible increased concentration of chemicals and their compounds may be caused by contamination of the source by fertilizers, or by wastewater from industrial facilities, or due to an industrial accident with a hazardous substances leak.This risk is also reported to be significant in studies by Yang et al. [15] or Lendowski et al. [16].Industrial accidents and their impact on drinking water supply are also discussed in the article by Szpak D. and Tchórzewska-Cieślak B. [17].Operator A (small municipality-independent operating model) monitors water quality only to the mandatory extent, it does not carry out its own extended water quality checks of the water source, which is linked to the low detectability of these risks.For Operator B (mixed operating model) this risk was assessed as moderate and mainly related to the surface water source (Operator B uses a multi-source system-water from the Elbe River and groundwater sources).Therefore, as a recommended measure to mitigate this risk, it was proposed to carry out extended inspections beyond the mandatory scope, on the operator's own initiative.Increased preventive and control activities on the part of industrial companies and inspections of hazardous activities in the protection zones of water sources are also possible measures to reduce the risk.Operator C uses a multi-source system (reservoir water and groundwater wells), three water protection zones, and also carries out inspections of activities in the protection zones.It compensates farmers who cultivate fields close to the surface water source and achieve lower production yields due to more environmentally friendly fertilization practices, i.e., it tries to prevent contamination of the source and has an elaborate system of measures in place.
Possible contamination of the source with synthetic pharmaceuticals and phytopharmaceuticals is another identified risk.This risk was evaluated as significant for all operators assessed.Pharmaceuticals can enter water sources through various routes and can affect not only the environment but also the health of consumers.Recently, therefore, in addition to the classical indicators, so-called micropollutants have also been investigated in drinking water analyses.Some pharmaceuticals can change form and become resistant metabolites.These risks are also mentioned in the 2020 EurEua report, which identifies micropollutants from pharmaceuticals (including veterinary drugs) as risks to water resources [1].Although the observed concentrations in water sources are currently low for most of them, these products can have a negative impact on aquatic ecosystems.This risk is also mentioned by Bottoni et al. in their study [18] and also by Félix-Cañedo et al. [19].Moreover, the detectability of these risks is difficult.In the Czech Republic, the State Environmental Fund of the Czech Republic is trying to address this by supporting innovative technologies that contribute to a demonstrable reduction in pharmaceuticals in wastewater.Operator A (a small municipality) makes only limited use of in-house water analyses, as monitoring instruments are costly.If the source is already contaminated, some commonly used measures cannot be used here, e.g., the municipality does not have interconnected water supply systems or its own backup water sources.Interconnecting water systems are certainly an effective solution, but they are too costly for small communities.Operator B monitors the presence of drugs in the water only once a year as part of a complete water analysis, which includes a total of 65 items (listed in Annex 5 to Decree No 252/2004 Coll., determining the sanitary requirements for drinking and hot water and the frequency and scope of the monitoring of drinking water).This complete analysis is costly for a medium-sized operator and is therefore carried out only at the interval specified in the decree.No other measures have been taken.Operator C carries out monitoring, but not on a continual basis.In addition, there is no recommended procedure.Operator C focuses its monitoring on pesticides rather than pharmaceuticals.Therefore, the proposed measure is to establish a recommended procedure, to adopt a list of priority substances, and to review and update it regularly.The proposed measures also include the continuous monitoring of pharmaceuticals and phytopharmaceuticals in the water treatment process, the use of a combination of aerobic and anaerobic treatments, and the use of advanced oxidation processes in the water treatment.The implementation of an information campaign towards the public on the management of unused medicines and trying to minimize the overuse of medicines is another proposed measure.
The other major risks identified are climate change related.Floods can pollute and devalue water sources, so the level of risk is high, as is the probability of its incidence, but the detectability of the risk is almost certain given the current high accuracy and success of hydrological flood forecasts.The most likely cause of flooding is snowmelt or torrential rainfall.The risk of prolonged drought has been, for most operators, assessed as severe with a medium probability of incidence.Existing measures to prevent these risks are the shutdown of the affected source while using an alternative or emergency supply of drinking water to the population.Natural risks and their impact on the drinking water supply are also addressed in the study by Szpak D. and Tchórzewska-Cieślak B. [17].Floods as a significant natural hazard for water resources are also mentioned in the study by Serra-Llobet, Conrad, and Schaefer [20].The impacts of climate change and the risks associated with water scarcity are also addressed in a study by Salehi [21].Operator A does not possess its own technical means (it does not have its own tankers or wagons) but can borrow them if necessary.Operators B and C already have their own technical means to provide emergency or substitutive drinking water to the population.The proposed measures to mitigate this risk include interconnecting water supply systems, whereby the water supply from a neighboring system can be used if necessary.Operator B is currently constructing interconnections and has developed drought management plans.Operator C already has interconnected systems and has developed drought scenarios projecting to 2050 with a good risk management set-up.Stockpiling drinking water in households in the recommended quantities belongs to other proposed measures as it is employed in many countries, while this study has developed recommendations for households in the Czech Republic on how to maintain drinking water stocks and how to proceed.The risk of deliberate contamination of the source by pathogens (bacterial, parasitic, and/or viral) was assessed by the expert team as a moderate risk with low probability of incidence, but also as an unpredictable risk.Only Operator C was assessed as having a high probability of detection of this risk as they have standard procedures in place to monitor and detect this risk.

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Water treatment The results of the risk analysis for each operator's water treatment are presented in Tables 11-13, yet only risks with an RPN of 20 or higher are shown.The results of the full FMEA method concerning the water treatment for all operators assessed are presented in Supplementary Material File S2.The facilities owned by Operator B are secured, regular monitoring of water quality is carried out, and a risk assessment and management system is in place.The most significant identified water treatment risks (RPN greater than 20) for Operator B are shown in Table 12.
Operator C's facilities are sufficiently secured and monitored by CCTV, the operator invests in maintenance and modernization of the facilities, uses its own laboratory system, control processes and risk assessments, and management processes are well set up.The most significant identified water treatment risks (RPN greater than 20) for Operator C are shown in Table 13.
In water treatment, the risks of power outage or failure of electricity supply and the risks of cyber -attacks were assessed as the most significant.The risk of power outages in the drinking water supply has been addressed in studies by a number of authors, e.g., Busby et al. [22] or Bross et al. [23].
As for outages or failure of electricity supply, the level of risk was assessed as critical, with a medium-high probability of incidence.The analysis showed Operator C as the best prepared to manage this risk.In the event of an outage, they can use their own back-up power sources as well as automatic booster stations using generators.Operators A and B do not own any back-up power sources (diesel generators) but can borrow them if necessary.Building photovoltaic plants is a recommended measure to mitigate this risk, and Operator C is currently preparing an investment plan to build its own photovoltaic plant.However, this is a financially challenging solution for operator B (he is trying to keep water prices at an acceptable level and therefore does not have enough funds for this investment), which applies also for small operator A. Another proposed measure is to increase operators' preparedness for this emergency situation, e.g., by practicing a blackout.Operator C took part in a regional blackout drill in 2018 together with other operators which included a test of preparedness to provide emergency drinking water to the population in the event of a large-scale power outage over a large area.The preparedness for such a situation is also addressed in the emergency preparedness plans of the individual operators; nevertheless, these are often not regularly updated at the level of small operators.
The risk of cyber -attacks was assessed as the most significant one for Operator B. Protecting water infrastructure from cyber -attacks is also addressed by Robert M. Clark et al. in their article "Protecting Drinking Water Utilities from Cyberthreats" [24].The current trends and challenges in cybersecurity in the water sector are also addressed by Alabi et al. in their article [25].In the Czech Republic, a proposal to amend the Cybersecurity Act, which transposes the European Directive 2022/2555 [26] into the Czech environment, was submitted in 2023.The consequences of a cyber-attack could include limiting the functionality of information systems, disabling the water treatment plant's control systems, and disrupting operations.The most common cause may be a hacker attack.Medium-sized operators, in particular, are a good target for a potential hacker attack, as they usually do not have sufficiently secured computer networks, do not regularly train employees in cyber security, etc.For Operator A (small municipality), this risk was assessed as low with a very low probability of incidence due to the size of the operator.For Operator C, the risk was assessed as less severe with a medium probability of incidence.Operator C has established its own cyber security center and uses SMART dispatch.It also regularly trains its staff in digital security and regularly updates its security measures.The voluntary and consistent implementation of safety precautions and control systems ensuring the highest level of protection as well as consistent training of employees in digital security are also among the measures proposed to mitigate this risk.
For small operator A, other risks were identified and rated as significant by the expert team, one of which was the poor structural condition of the facilities (neglected maintenance of walls, deteriorated operating conditions, etc.), possibly resulting in water contamination.In such cases, financial motivations for small operators to set up a risk management system, imposing fines in the case of neglected maintenance or when detecting deteriorated operating conditions, are proposed as possible recommended measures.The human factor also plays an important role and, of course, it is not only small operators who nowadays face a shortage of qualified staff.The inadequate security of the water treatment facility and possible intrusion by unknown/unauthorized persons were also assessed as a very serious risk for Operator A. Here, it is necessary to ensure that the security of the facilities is tight, that the operating regulations are strictly followed, and that small operators take more initiative to increase the security of their facilities.
For Operator A, the risk of using inappropriate chemicals for water treatment (or in inappropriate quantities), either due to the poor technical condition of certain parts of the water treatment line or due to human error, was assessed as a moderate risk.The solution here would be to use automated systems, which is, however, very costly for small operators.Similarly, the acquisition of containerized water treatment plants is financially unaffordable for most small operators.

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Water distribution The results of the risk analysis for each operator's water distribution are presented in Tables 14-16 and only risks with an RPN of 20 or higher are shown.The results of the full FMEA method concerning the water distribution area for all operators assessed are presented in Supplementary Material File S3.The most significant water distribution risks for Operator B are listed in Table 15.
Table 16 shows the most significant risks identified for Operator C in the areas of water distribution.
In the water distribution area (reservoirs and water network), the highest level of risk for all selected operators was identified as the risk of pipe joints breaking, due to the aging of material.The level of this risk was assessed as very serious with a high probability of incidence.In addition, this risk was assessed as difficult to predict.The recommended measures to mitigate this risk are the regular specialized renovations of the water network (which is, however, costly for small-and medium-sized operators) and the choice of appropriate materials to increase lifespan.Disruption of pipeline joints can also be caused by the corrosion of the material (caused by "soft water" in Operator B), in which case it is resolved through the proper regulation (reduction) of pipeline pressures and by dividing the pipeline into pressure zones.The composition of the water itself has a significant impact on corrosion as it is affected by the temperature of the water, its pH, the total number of magnesium and calcium cations (the so-called hardness of the water), the soluble oxygen content, and others.The risk of corrosion mainly concerns groundwater sources and, thus, it is necessary to select appropriate materials to increase the lifetime of the pipes (e.g., plastic, cast iron, etc.).Operator C uses special cameras to diagnose the condition of the pipes.
In the area of water distribution, power cuts were also identified as a significant risk as it was assessed as moderate in the water distribution area with a medium probability of incidence.Furthermore, this risk was rated as difficult to predict.Existing and recommended precautions have already been defined in the text above.
For Operators A and B, neglected maintenance was identified as another significant risk which is mainly caused by the lack of financial resources for maintenance and the lack of qualified staff.The recommended measures to mitigate this risk are to increase funding for the maintenance of the water network, to train staff, and to define their required qualifications and responsibilities.
Operator C owns backup sources of electricity and technical means to ensure an alternative or emergency supply of drinking water to the inhabitants.It has its own backup water sources and interconnected water supply systems and is currently planning to build its own photovoltaic plant.

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Limitations of the study Of course, the analysis presented here has its limitations.The sample of operators is small, which is the biggest weakness of the analysis.Therefore, the selection of the evaluated operators representing each operating model was carried out by an expert group and the results of the analysis were consulted and confirmed with experts.However, this limitation should not have any impact on the global picture received.

Conclusions
Since the Czech Republic is one of the few countries with predominantly delegated private administration [1], this paper focuses on the most commonly used models of operating water supply systems in the Czech Republic.The study also identifies the strengths and weaknesses of each operating model.Individual models can be assessed from different perspectives-economic, technical, in terms of specialized security of operations, resilience to risks, etc.The model of independent operating, where the municipality sets its own price for water and sewerage charges while being able to subsidize itself, appears to be the most advantageous in terms of price for the end consumer.Although the smallest municipalities charge their own water and sewerage charges, they lack the financial means for future infrastructure renewal.In 2020, the Ministry of Agriculture updated the methodological guidance on the standardized preparation and documentation of the implementation of the "Water Supply and Sewerage Restoration Financing Plan"; however, particularly for small owners and operators, it is often impossible to raise sufficient funds from the collected water and sewerage charges to restore their assets [27].Even the 2021 "State of Water Management Report" points to the complete absence or incorrect elaboration of the "Restoration Financing Plan" as a recurring major fault in the audits carried out by the Ministry of Agriculture in small operators [28].As for the sufficient technical security as well as specialized security of the operations, the mixed and compartmentalized operating models seem to be more suitable.This finding is consistent with the Ministry of Agriculture statement that during the 2021 inspections it was repeatedly found that some of the expert representatives of small operators were performing their jobs rather as a matter of formality, either because of financial remuneration or because of their limited availability within some regions [28].In terms of risk resilience, the compartmentalized model seems the most appropriate, as such a large professional provider is well prepared for most risks based on the performed analysis.
The results of the analysis therefore show that small water supply systems are most at risk.The small operator (independent operating model) does not have sufficient financial resources for the regular maintenance and renovation of the water supply network, does not have its own means to ensure an emergency drinking water supply, monitors water quality only to the mandatory minimum extent, and does not have sufficient resources to adequately secure the facilities.It does not have water and electricity backup sources and is not prepared for most of the identified risks, in the case of emergencies.
This conclusion corresponds with the conclusions of the 2020 "Financing Water Infrastructure" conference, where Jan Kříž of the Ministry of the Environment called for the sector to be grouped into larger units: "Should the sector be self-sustainable and subsidy-free, it is not possible to do so without solving its fragmentation.Let's look for ways to form associations.The systems will then be much more effective" [29].
We believe that the results of our study will be relevant not only for the operators themselves, but also for those responsible for the operation, for municipal representatives, as well as the contractors, as they can hopefully better understand the advantages and disadvantages of the different models of operation and adapt the models used to their specific needs.

Figure 1 .
Figure 1.Flowchart of the proposed FMEA model (own source).

Figure 1 .
Figure 1.Flowchart of the proposed FMEA model (own source).

Table 1 .
An overview of the possible operating models in the Czech Republic.

Table 2 .
Level of risk (own source).

Table 3 .
Probability of risk (own source).

Table 7 .
Analysis of strengths and weaknesses of the compartmentalized operating model (own source).

Table 8 .
Top identified water source risks (RPN higher than 20)-Operator A (independent operating system).

Table 9 .
Top identified water source risks (RPN higher than 20)-Operator B (mixed operating system).

Table 11 .
Top identified water treatment risks (RPN greater than 20)-Operator A (independent operation).

Table 14 .
Top identified risks in water distribution (RPN greater than 20)-Operator A (independent operation).

Table 15 .
Top identified water distribution risks (RPN greater than 20)-Operator B (mixed operating model).