In order to run a quick test on an old home, simply turn on the hot water and let it run for a minute or two. If you see the water pressure is low, it is likely the house has galvanized pipes that have tarnished and plugged up over time. In this scenario, the hot water pipes should be the first thing to get rid of.
It’s important to note that if you see no problems or concerns with the water pressure, that doesn’t mean everything is necessarily fine. It is possible that the house could have good pressure in the hot-water lines, but still have hidden problems caused by galvanized pipes. Some old houses may have had all of the bad pipes replaced, but still have many old galvanized pipes that will soon be in need of replacement.
Although some experts may tell you to replace the entire piping system once galvanized piping starts to create problems, many homeowners cannot afford such an expense and end up only fixing the pipe causing the immediate problem. What’s even worse, replacements may have been done using more galvanized pipe instead of plastic or copper pipe, which only extends the problem instead of solving it.
Obviously since most plumbing systems are behind walls, it can be difficult to determine the full scope of plumbing problems. Often times new piping and plumbing can be easier to spot because new pipes are usually run through the floor under the sink; Therefore, looking under the sink can help to determine if indeed the house has any new plumbing.
If copper piping has been attached to galvanized pipes, corrosion will occur because of the two different metals touching. A process known as dielectric coupling is required to stop this corrosion from taking place, which a professional plumber would know how to do correctly. If the re-plumbing was done by a non-professional, the dielectric coupling may not have been included.