This could be due to your pressure balance faucet in the shower rather than your water heater itself. Pressure balance and temperature control shower faucets tend to reduce the water pressure while using the faucet. A temperature control shower faucet uses a spring that adjusts the water pressure when it senses a rise in the water temperature; when the spring gets old, it could affect the temperature of your water.

Cold temperatures can cause the metal on your water heater to expand and contract, which could lead to damage and eventual leaks. This is more likely to occur if your water heater is on the older side or is located in an area of your home that is unheated. To prevent this, schedule routine winter maintenance for your water heater and be sure to drain your water heater at least once per year to rid it of damaging sediment buildup.

This noise is usually the result of expanding water escaping from sediment at the bottom or your water heater tank. While this isn’t dangerous, it can be a sign that your water heater has lost efficiency. As sediment build up in your tank, more heat is lost up the chimney and less gets into your water. Overheating the bottom of your tank also affects the overall service life of your water heater.