Ask a plumber why a water heater died at year seven instead of year twelve, and the answer is usually the same: nobody ever flushed it, and nobody ever checked the anode rod.
Water heater maintenance is genuinely simple. It’s just invisible, so it never gets done.
What sediment actually does
Every gallon of water entering the tank carries dissolved minerals. Heat drives them out of solution and they settle to the bottom as a hard grey layer.
In a gas tank, the burner is underneath. That sediment layer sits between the flame and the water, so the steel has to get hotter to push the same heat through. Hotter steel fatigues faster, which is how tanks develop bottom leaks. It’s also what causes the rumbling or popping sound — water trapped under the sediment flashing into steam.
In an electric tank, the sediment buries the lower element, which then burns out. That’s the most common electric failure there is.
The anode rod is the whole game
Your tank is steel with a glass lining, and that lining always has imperfections. To stop the exposed steel corroding, manufacturers hang a rod of magnesium or aluminium inside — a more reactive metal that corrodes preferentially. It’s called a sacrificial anode, and the name is literal.
Once the rod is consumed, the tank itself becomes the thing that corrodes. That’s the point at which the countdown to a leak starts.
A rod typically lasts three to five years. Replacing it costs a fraction of a new tank and can double the working life of the unit. Almost nobody does it.
A realistic schedule
- Every year: flush several gallons from the drain valve until it runs clear. Test the T&P valve by lifting the lever briefly and confirming it reseats without dripping.
- Every three years: have the anode rod inspected. If it’s down to the core wire or heavily pitted, replace it.
- Every year on tankless: descale with a circulation pump and a suitable solution. Tankless units have narrow heat exchanger passages and scale kills them quickly.
- Ongoing: keep the thermostat around 120°F. Higher accelerates scaling and corrosion, and it’s a scald risk.
The one that catches people out
If the tank has never been flushed and it’s already several years old, opening the drain valve can dislodge sediment that was effectively acting as a plug — and the valve may then fail to reseal. That’s not a reason to avoid maintenance; it’s a reason to start early and stay consistent, and to have a plumber do the first flush on a neglected unit.
Water hardness changes everything
Hard water dramatically accelerates all of this. In hard-water regions, annual flushing isn’t optional and anode rods wear faster. A softener protects the water heater as much as it protects your fixtures.
We handle this alongside our other work here in Rochester — see our residential leak repair service for what happens when a neglected tank finally lets go. Readers in Southern California, where hard water is the norm across much of the region, can get maintenance and replacement handled by water heater specialists in Covina, CA.
Worth the hour
An annual flush and a rod check every few years is perhaps an hour of work a year. Against a tank replacement plus whatever the leak damages on its way out, it’s the best-value maintenance in the entire house.
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