What is the ruling on working for a government company that sells water to citizens for consumption bills, knowing that the sources of water are diverse (groundwater, dams, and desalinated from the sea)?

It is permissible to work for a company that extracts groundwater, collects rainwater and river water, or desalinates seawater and sells it, because it has expended money and effort in doing so. However, if it sells water in its natural place without expending effort in collecting it, preserving it, or treating it, then it is not permissible for it to sell it or prevent others from it.