Conventional storage-tank water heaters are surprisingly simple devices. Their designs can vary depending on fuel source and model, but they all have the same essential elements. These components typically include a heat source, thermostat for temperature control, anti-corrosion elements, and various hook-ups for water and fuel.
Despite this simplicity, your water heater is vulnerable to several issues that can lead to costly repairs. Hard water—which refers to water containing significant mineral deposits—is one such threat. If you aren't letting the hard water in your home bother you, then you may have some expensive water heater repair bills in your future.
Why Does Hard Water Affect Appliances?
Although it can be a nuisance, hard water is not dangerous. Magnesium and calcium are not harmful (and may even be healthy), and these are the two minerals that commonly appear in water with high hardness levels. Unfortunately, minerals that aren't hazardous for human consumption can still pose a severe threat to plumbing and appliances.
Water develops hardness as it passes through rocks containing these minerals. When mineral-rich water enters your plumbing, the calcium or magnesium can leave behind "scaling" on pipes, fixtures, and inside of appliances. This situation can be especially disastrous for water heaters of all designs with any fuel source.
Scale Build-Up and Your Water Heater
Scale can develop on any surface that comes into contact with hard water, but hot water can accelerate the reaction. In other words, your hot water tank is one of your home's most vulnerable appliances if you have a hard water problem! In most tanks, there are three elements inside the tank that hard water may damage: the heating elements, the anode rod, and the thermostat.
You may develop scale build-up on the heating elements themselves for electric water heaters since they remain immersed in water. If the problem goes unaddressed, you'll usually have to replace the heaters. For gas tanks, scale build-up along the bottom can insulate the tank and ultimately cause the burner to overheat. In both cases, your tank will operate inefficiently and cost more to run.
The anode rod and thermostat are also vulnerable to damage. If the anode rod becomes coated in limescale, its ability to protect the tank against will diminish. This issue is severe enough that it can destroy your entire tank if you ignore it. Likewise, the temperature sensor on your thermostat may become covered in limescale, preventing it from accurately reading your water temperature.
Repairing and Preventing Problems
If you've been living with hard water, then your water heater may already be in trouble. A plumber can help you to evaluate its condition and recommend any necessary residential water heater repairs or maintenance to restore it. If you have severe issues with hard water, then you may need to discuss water softening options with your plumber to help avoid more repairs in the future.