Anode Rods
An anode rod is a length of magnesium that threads into the tank and corrodes on purpose, so the tank metal doesn't. Steel-tank heaters rely on one and you swap it when it's eaten down to the wire; a badly corroded rod means it's been earning its keep. The Camco rods here are magnesium on a 1/2-inch NPT thread, sized for Atwood-style tanks in 9.5-inch and 4.5-inch lengths, with one version that adds a built-in drain valve.
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Choosing an anode rod for your RV water heater
Three things decide whether a rod fits and how long it lasts: the thread, the length, and the metal. Get the thread and length right or it won't seat and seal; get the metal right and it matches how your water and tank behave.
- Thread and length. The Camco rods here use a 1/2-inch NPT thread and come in 9.5-inch (sized for 10-gallon Atwood-style tanks) and shorter 4.5-inch lengths. Measure the old rod and match it — a too-long rod bottoms out, a too-short one under-protects.
- Magnesium vs aluminum. Magnesium is the standard and protects most aggressively. Aluminum tends to last longer and holds up better in hard or high-sulfur water, and it's the usual answer to a rotten-egg smell in the hot water.
- Steel vs aluminum tanks. Steel tanks (Suburban) depend on a sacrificial anode and must always have one in place. Aluminum tanks (Atwood and aluminum-tank Dometic) resist corrosion differently — the drain-valve rod here doubles as your drain plug so you can flush the tank from the same fitting.
- Replacement interval. Pull and check the rod once a season. Replace it when it's down to about a pencil's thickness or heavily pitted; a rod eaten to the core stops protecting, and the tank starts corroding instead.
Draining and flushing the tank whenever you change the rod clears the sediment that shortens a heater's life, so fold it into any element or thermostat service. If you're deep enough to be pulling the whole unit, browse complete water heater tanks, and keeping the fresh water system clean upstream helps the rod last longer too.