What are common signs of a failing water heater?

The choice identifying water discoloration, strange noises, and an inconsistent hot water supply as common signs of a failing water heater is correct because these symptoms directly indicate issues with the internal functioning of the unit.

Water discoloration may suggest rust, sediments, or mineral buildup inside the tank, which can lead to reduced efficiency and water quality. Strange noises, such as popping or rumbling sounds, often occur due to sediment accumulation at the bottom of the tank, which can affect heating efficiency and eventually cause damage. An inconsistent hot water supply is a clear sign that the heater is struggling to maintain the desired temperature, possibly due to failing components or improper heating elements.

These signs collectively point to significant operational problems that require attention to prevent complete failure of the water heater, ensuring both safety and comfort in the use of hot water in a residential setting.