The answer to 'why is my water line no hot water' is that the most common causes are a faulty water heater, a broken thermostat, or a problem with the water supply line. Without hot water coming from your taps, it could indicate an issue with the heating element, thermostat, or plumbing connections in your water heater. This can lead to no hot water being delivered to your fixtures.
If you have no hot water, first check your water heater to ensure it's powered on and the thermostat is set to the correct temperature. You can also try resetting the breaker or pilot light. If those basic troubleshooting steps don't resolve the issue, it's likely a more complex problem that will require a professional plumber to diagnose and repair, such as a faulty heating element or sediment buildup in the tank.