Modern water heaters are very reliable and robust, but they are not invulnerable to damage. Constant exposure to heated water can cause damaging rust and corrosion of your heater's metal components, and without some form of protection, a standard water heater would be crippled by rust in a matter of weeks.
Most types of water heaters (excluding tankless heaters) are fitted with simple devices known as anode rods, which protect the heater against rust. If the anode rod in your tanked water heater is starting to fail, it can cause a variety of serious problems.
How Do Anode Rods Work, And Why Do They Fail?
Most anode rods fitted to tanked water heaters are sacrificial anodes, which are made from metals that corrode readily when exposed to moisture. Magnesium is the most common metal, but your heater may be fitted with an aluminum or aluminum/zinc alloy anode if the water supplies in your area are relatively hard.
These anodes rely on a basic scientific principle known as cathodic protection. Because they are more reactive to water than the metal components of your heater, they corrode more quickly, which slows corrosion of the other components. Depending on the metal your anode is made from and the composition of your water supply, an anode may provide corrosion protection for up to five years.
However, once the anode has become extensively corroded, it can no longer protect the surrounding metal. Water heaters with old, worn-out anodes can suffer a variety of problems and are much more vulnerable to corrosion.
If your water heater is relatively new, it may be fitted with a titanium anode. These are not sacrificial anodes; instead, they create an electrical charge that prevents water from corroding the heater's metal components. However, if the anode's power supply fails, it can cause the same problems as failed sacrificial anodes.
How Can You Tell If You Need A New Anode Rod?
If the anode rod inside your water heater's storage tank has failed, you may notice some or all of the following problems:
- Brown or discolored hot water
- Hot water that smells like rotten eggs
- Loud knocking and/or popping noises when the water heater is activated
- A slimy substance accumulating inside your hot water faucets and faucet aerators
If your water heater has not been fitted with a new anode rod in the last five years, you should also assume that your rod has either failed or is on the verge of failure.
What Should You Do If Your Anode Rod Fails?
If your water heater is suffering from problems and you think a failed anode rod is to blame, you should not try to replace it yourself. An improperly fitted anode rod can cause more problems than it solves, and you may be unable to remove the rod safely if corrosion has caused it to swell.
Instead, you should call in a professional plumbing repair service ASAP to have the anode inspected and replaced. Professional plumbers can do more than simply replace your failed rod; they can also recommend rods made from different materials if yours is fitted with an unsuitable rod, and can offer water treatment services that will make your new rod last significantly longer.