Plumbing works are really hard and take time to do. As most of us hiring plumbers we don't know what is the actual work or process is happening there. Usually, plumbing system in most our houses contains two subdivisions. One intake the fresh water and the other outtake the water. The water is comes under pressure to travel to all the places around your house such as corners, upstairs, etc. A meter is attached to this to see the usage of water. There will the main shut off valve near the meter. For the emergency, you can turn off this valve instead of turn off the entire supply. So it is advisable to use the separate valve for your water supply. I hope you have had some idea about how plumping work is taken place. Here is a YouTube video which explains how you can repair or fix the whining water pipes with yourself.