# Water Supply Systems for Settlements with Arsenic-Contaminated Groundwater--Making the Right Choice
## 4 Conclusions  
This paper presents two possible water supply strategies for rural regions that have serious problems with natural arsenic contamination in their drinking water sources. Two municipalities in Vojvodina, the northern region of the Republic of Serbia, were used to demonstrate the two different approaches: in the first approach, each settlement has their own WTP, and in the second, settlements are connected to a centralised (microregional) system. In regions like this, with a large number of small settlements, strategies should focus on finding techno-economically and socioeconomically appropriate solutions to secure safe drinking water supply, both in terms of delivering the required amounts of water and in terms of quality.  
Several possibilities should be taken into consideration, such as treatment of the water from the existing source and exploring opportunities to include nearby settlements in microregional water systems with other water sources (connecting several settlements or municipalities in a single unit depending on available water sources). Water treatment technologies must be appropriate for a given quality at each location individually, relatively easy to control, and in case of accident, reconstruction should be prompt. Thus, local or microregional systems have to be designed and implemented in a modern manner, at a high technological level, in order to permanently secure an adequate regional system in the future.  
The methodology used in this paper applies a number of cost approximations to evaluate and compare the localised and centralised systems. The approach was kept deliberately simple in order to create a clear argument that may be readily presented to local authorities and policy makers, with the aim of supporting a viable strategy for water supply for an entire region. Once such a strategy is in place, detailed feasibility studieswould be required to fully define and specify the actual water supply infrastructure. In the meantime, it is worth noting again the clear long-term economic benefits of a centralised system demonstrated for both municipalities in this paper. Decentralisation has gained increasing popularity as a strategy for public infrastructure development, especially in the field of wastewater treatment. However, when the additional benefits in water quality security brought about by centralisation are weighed against the negatives, centralised water supply systems likely represent the best choice even in rural regions.  
Conceptualisation, J.A. and A.T.; methodology, A.T. and U.S.; formal analysis, M.K.I. and J.A.; resources, B.D.; data curation, J.A. and M.W.; writing--original draft preparation, J.A., A.T. and M.W.; writing--review and editing, J.A. and M.W.; visualisation, M.K.I. and U.S.; supervision, J.A.; project administration, J.A. and B.D.; funding acquisition, J.A. and B.D. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Science Fund of the Republic of Serbia Program DIASPORA, #6485164, HYDRA project.  
Not applicable.  
The data presented in this study is available from the corresponding author.  
The authors would like to thank [PERSON] of KWR Institute for his assistance in the implementation of the #6485164 HYDRA project, funded by the Science Fund of the Republic of Serbia.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.