A new tank water heater should be replaced every 10-15 years, and a new tankless system every 20 years, as a general rule.If you don't know how old your water heater is, you can typically find out by looking at the serial number, which is normally located someplace on the device.Strange noises or odors emanating from your system or appearing in your water, inconsistent water temperature or flow, and rising energy bills are all symptoms that it's time to replace your water heater. For more information, please visit Sopindy