If you own a storage-tank water heater, you’re not alone. Most homes in Denver, CO, and elsewhere also depend on one. There are a variety of reasons why. One is that storage tank water heaters are inexpensive, reliable, and long-lived. They also require very little maintenance.
The one major exception is a single, consumable device inside your water heater that needs periodic replacement. It’s called an anode rod, and it plays a critical role in the longevity of your water heater. Here’s everything you need to know about anode rods, from their purpose to how you can tell you need a new one.
What Is an Anode Rod?
An anode is one of the two poles of an electrical circuit. More specifically, it is the pole that oxidizes, shedding electrons to create an electrical current. That is why an anode rod in a water heater is sometimes called a sacrificial anode. A water heater anode rod is a metal rod that encloses a steel wire. It typically screws into the top of a water heater tank, making replacement easy. Most water heater anode rods consist of aluminum, magnesium, or a zinc-aluminum alloy.
What Is the Purpose of an Anode Rod?
In a water heater, an anode rod protects the inside of the tank from oxidation. It does so by introducing a metal surface inside your water heater that’s quite vulnerable to corrosion. The anode rod attracts iron, limestone, and other mineral ions from your water. Those things would otherwise attack the tank’s metal, leading to its corrosion. The anode rod is an easier target that sacrifices itself to keep the inside of the tank intact.
Without an anode rod, the lifespan of a storage-tank water heater would be considerably shorter. Depending on the quality and content of your water, your water heater would likely fail without one before its 10th birthday. Worse still, the kind of failure it’d likely experience would be a large leak or a catastrophic tank rupture. If you replace your water heater’s anode rod when necessary, your water heater could last up to 30 years.
How Often to Replace an Anode Rod
Unfortunately, your water’s makeup and how much you use hot water can significantly impact the lifespan of an anode rod. Most water heaters need their anode rod inspected at least every three years. However, many will last at least five years. A qualified plumber can tell you when you need a new anode rod. If you ask them to show you the worn-out anode rod, it will be evident that it needs replacing. A new anode rod will look like a galvanized section of pipe. A worn-out one will be much thinner and severely corroded. A destroyed anode rod will look like little more than a wire suspended from a bolt.
If your home has a water softener system, you may need your anode rod inspected annually. Water softeners add sodium ions to your water in exchange for mineral ions. While that reduces limescale and the other effects of hard water, it can accelerate the corrosion of an anode rod. With a water softener in place, your anode rod may last three years or less.
Signs You Need a New Anode Rod
Aside from regular inspection, it isn’t always easy to tell when your anode rod requires replacement. However, a worn-out anode rod can cause some symptoms that alert you to a problem. They include the following.
Rusty Hot Water
When your anode rod corrodes, it shouldn’t have any noticeable effect on the quality of your water. So, if your hot water starts looking rusty, it’s a sign that something other than the anode is corroding. It could be a supply line, or it could be the inside of your water heater. Either way, you should have one of our plumbers investigate the problem. If your anode rod needs replacement, they’ll take care of it for you.
Smelly Hot Water
If your water heater has an aluminum or magnesium anode rod, it may produce a rotten egg smell when nearing failure. That’s an indication of the advanced corrosion affecting the metal. As the anode rod wears down, it corrodes faster and faster. Its metal may react with sulfites in your water to produce hydrogen sulfide at sufficient concentrations. That substance is the source of the smell. Regardless, unusual smells from your hot water should always prompt a visit from one of our plumbers.
Hearing Pops and Bangs
Whether you have a natural gas or electric storage tank water heater, it should operate silently. You may hear water flowing into and out of the tank at most. So, if you hear popping or banging noises from your water heater, something’s wrong. The sounds often come from mineral deposits in your tank cracking from the water pressure. Since one of the anode rod’s jobs is to suppress mineral buildup, the sounds may indicate a need for a new anode rod.
Less frequently, the sounds may originate from the tank itself. In that case, it could indicate severe tank stress, likely resulting from a long-depleted anode rod. Unfortunately, replacing the anode rod won’t help much in those situations. If the tank material is already corroding, a new water heater is a wise investment to avert a costly failure. And when you get your new water heater, remember to have its anode rod periodically inspected to avoid repeating the problem.
Non-Sacrificial Anode Rods
Although most storage tank water heaters come with sacrificial anode rods, they aren’t the only option. There are also non-sacrificial anode rods that use electricity to serve a similar purpose. Some high-end water heaters have powered anodes built in, and there are aftermarket add-ons for those that don’t have one.
Non-sacrificial anode rods rely on a concept called impressed current cathodic protection. In short, they turn your water heater into a sort of reverse battery. Inside a battery, an anode gives up its electrons via corrosion, which travel to a cathode. That flow is the electricity the battery yields. Without a sacrificial anode, the inside of your storage tank becomes an anode by default.
A powered anode injects a small flow of current into the inside of your storage tank. That forces the tank’s interior to act as a cathode and accept electrons rather than corroding. However, since the electric current comes from a power outlet, the anode doesn’t corrode, either. As a result, a powered anode can last for the whole life of your water heater without replacement. However, it’s important to know that power outages will leave your storage tank at the mercy of corrosion. So, if you install a powered anode, it either needs a battery backup, or you’ll need to drain your water heater during any lengthy power outage.
Your Local Water Heater Experts
If you need a trustworthy plumber to inspect or replace your water heater’s anode rod in Denver, Summit Heating, A/C, Plumbing & Electrical can help. We’ve served residents of the area since 1998, building a reputation for quality service. Our plumbers are highly trained and experienced, and we’re licensed, bonded, and insured for your protection. So, if you need water heater maintenance, including anode rod replacements in Denver, call Summit Heating, A/C, Plumbing & Electrical today!
