Water company
It's difficult to find the place the first time and locals don't seem to know how to give directions, but can't be blamed, the zone is a terrible maze. Just ask for "la plaza de futbol de sonafluca" then you'll find it in front of it, right next to the high school. Be patient and always smile because they have a heavy bureaucratic process, and will not help you much, make sure to bring all your papers and fotocopies of all of them, including your ID.