Lowe's states that the lifespan of a water heater is 8 to 12 years. The actual time of replacement depends on the workmanship of the original installation, the weather, the frequency of use and the quality of the heater itself.
Many water heaters work well for 10 years or more. If the water heater starts to leak or if it stops working, it may need to be replaced.
Not all problems require replacement. Common water heater issues are caused by blown fuses, broken thermostats and faulty heating elements. Other problems can be caused by leaking hoses, sediment build-up, and faulty or leaky water pipes.