We have a ranch home with 3-1/2 bathrooms (one full located in the basement)-built in '93. Our master bath shower rarely has hot water, but the rest of the showers have hot water. Even if I'm the first one to shower, the water is never hot enough. We've had the hot water heater checked and it's fine.
COMMUNITY FORUM
There are several possibilities
1- Uninsulated piping
2- Thermostatically /pressure controlled valve not set properly
3- Hot water line taken from a hot water return rather then a supply line
4- Cross connection allowing mixing of hot and cold water supply tempering the water to a much lower then desired temperature
5- Ambient temperature cooling the hot water line possibly to close to an outside wall
There are other causes but this is a decent place to start looking
1- Uninsulated piping
2- Thermostatically /pressure controlled valve not set properly
3- Hot water line taken from a hot water return rather then a supply line
4- Cross connection allowing mixing of hot and cold water supply tempering the water to a much lower then desired temperature
5- Ambient temperature cooling the hot water line possibly to close to an outside wall
There are other causes but this is a decent place to start looking
