How many gallons / litres is your home water heater?
We live in a suburban 4 bedroom detached home. I find that after my wife and kid shower, I’m stuck showering in cold water.
Are they using too much water or is my water heater just not big enough?
Edit: not my photo. We currently have a 50gal tank.
You could have a broken dip tube. The dip tube mixes the incoming cold water with the hot water. If it’s broken then the water at the top of the tank gets cold and the outgoing water comes from the top.