Plumbing fixtures are fairly simple mechanisms, which makes it easier to identify problems when they pop up. For example, when you turn on your faucet, and the water comes out the perfect temperature, only to change dramatically when someone flushes a toilet, then you most likely have an issue with your anti-scald valve. The issue could be that you don’t even have one installed.
Anti-scald valves mix the water in your pipes to attain a stable temperature of the incoming water. Even more importantly, just like their name indicates, they will prevent scalding. The water coming from your water heater could be hot enough to cause scalding in just a few seconds. This is especially dangerous for young children or elderly ones that might not be able to react fast enough. If there is an issue with your anti scald valve, or if you need one installed, a plumber should be able to care for that easily.