Most of us enjoy taking a hot shower to loosen up stiff muscles and just relax. We all have a different level of heat that we can handle, and what some might view as too hot is just right for someone else, but have you ever had the experience where your shower just got way too hot really fast? In some homes, these fluctuations happen when someone is using water somewhere else in the building. This issue is more common in older buildings, but it could happen to you if you have an issue with your pressure-balancing valve. This could happen because of mineral buildup or possibly just old age. If so, you should make sure to have it fixed by an experienced plumber. If the issue is ongoing, it could also be something simple like the main shut-off valve for your cold water. Maybe someone bumped into it or a kid played with it and it got partially turned off. That could explain the imbalance that you are experiencing.