The part you've never heard of that keeps your tank from rusting out.
Inside your water heater tank, there's a metal rod you've probably never seen or thought about. It's called the anode rod — and it's the reason your tank hasn't rusted through yet.
Understanding what it does helps you make better decisions about water heater maintenance. It's also something plumbers check when they service your heater — and for good reason.
Your water heater tank is made of steel. Steel rusts when exposed to water. So why doesn't your tank rust from the inside out?
The anode rod. It's a metal rod (usually magnesium or aluminum) that hangs inside the tank. Through a process called galvanic corrosion, the rod attracts the corrosive elements in your water — so they attack the rod instead of the tank walls.
Think of it as a sacrificial part. It corrodes so your tank doesn't have to.
The rod is designed to be consumed over time. As it corrodes, it protects the tank. When the rod is mostly gone, the corrosive elements start attacking the tank itself.
This is why anode rods need to be checked and eventually replaced. A depleted rod means your tank is no longer protected — and rust damage is often irreversible.
It depends on your water quality:
Most manufacturers recommend checking the anode rod every 2-3 years. If more than 50% of the rod is corroded, it's time to replace it.
You can't see the anode rod without removing it, but some signs suggest it's time to check:
Technically, yes. Practically, it's difficult for most homeowners.
If you hire a plumber:
Many plumbers include anode rod inspection as part of a water heater flush service. If you're already having maintenance done, it's worth asking them to check it.
Anode rods and sediment are both maintenance issues — and they're often addressed together.
When a plumber services your water heater, they typically check both. It's more efficient than addressing them separately.
The anode rod is a cheap part that protects an expensive appliance. Replacing a $30 rod every few years is far better than replacing a $1,000+ water heater early.
If your water heater is more than 3-4 years old and you've never had the anode rod checked, it's worth doing. Most plumbers can inspect it quickly during a routine service call.
Not sure about your anode rod? A licensed plumber can check it in minutes and let you know if it needs replacing. If you'd like to schedule an inspection, call 855-755-4920 to speak with a local professional.