RV water heater anode rod finder
Whether an RV water heater takes an anode rod is decided by the metal its tank is made from, and the two look alike from outside until the drain fitting comes out. Suburban builds porcelain-lined steel tanks with a sacrificial rod inside. Atwood and Dometic build aluminum tanks that take a plug instead, and fitting a rod to one of those damages it. Answer what you can see and this lands on the maker's part number, on the answer that there is nothing to buy, or on how to tell the two apart at the fitting.
The questions go in order. Nothing is sent anywhere.
What name is on the water heater?
The name is on the data plate, on the heater itself behind the outside access door.
What an anode rod does, and why many heaters have none
A tank is protected two different ways and only one of them uses a rod. Suburban fuses a glass lining onto a steel tank and hangs a magnesium or aluminum rod inside it. The rod is the part that corrodes first, which is what it is there for, and it is meant to be consumed and replaced. Dometic builds the heaters that were sold as Atwood, and makes its tank from high strength aluminum with a thin clad layer fused over the top. That clad layer is already anodic to the metals in the water, which is the same job a rod does in a steel tank, so there is no rod to fit and no rod to change.
Both drain through one fitting low on the heater. It is what sits behind that fitting that differs, and it is why the brand decides the job.
Why fitting a rod to an aluminum tank is worse than leaving it alone
Dometic's manual is direct about it. Replacing the drain plug with an anode rod damages the coupling with cathodic action, and product damage is the result. The same manual states that aftermarket anode devices are not compatible with its water heaters and will void the warranty, in the same list as aftermarket heating elements.
So the honest answer for an Atwood or Dometic is nothing to buy. What that tank wants is the flush, which is the maintenance Dometic publishes a schedule and a procedure for.
The Suburban part numbers
233514, magnesium, and 233516, aluminum. Suburban's 2025 catalogue lists both as extended life anode rods, and they fit the same 3/4 inch port. The magnesium rod is the one Suburban's own accessory page names as the replacement for its tank water heaters, with the aluminum one listed beside it.
Take the old rod out with a 1-1/16 inch socket, which is the size Suburban's operation guide gives. Put a pipe thread sealant approved for potable water on the threads of the new rod. Suburban calls for that, and it is also what keeps the fitting from weeping.
How often, and how to tell a rod is finished
Suburban's operation guide gives both answers. The simple one is yearly: the rod will deteriorate under normal use, and because of that, replacement is recommended every year. The measured one is wear: replacement is recommended when consumption or weight loss is greater than 75 percent. Water with high levels of iron or sulfate speeds the rod up, so a heater on water with high iron or sulfate can eat a rod well inside a year.
Suburban states two consequences: operating the heater without the anode voids the limited warranty on the tank, and draining the tank whenever the RV is not in use extends the life of the rod.
Flushing the tank, on both kinds of heater
Sediment is the maintenance neither tank escapes. Suburban describes what it does: sediment on the bottom of the tank forms a layer of insulation between the burner and the water, it slows heat transfer, and it overheats the tank bottom, which weakens the steel and damages the glass lining. Dometic's manuals describe the same problem on an aluminum tank and give the procedure for clearing it.
The procedure is the same on both. Turn the water off, cut the heater’s power at its switch or breaker, and let it cool. Open the pressure relief (T&P) valve at the top of the heater to let air in, and pull the anode rod or drain plug at the bottom to let the water out. Once it is empty, leave the bottom open, close the T&P valve, and turn your city water on for a few seconds. The incoming pressure blasts right across the bottom of the tank and flushes out the loose sediment naturally through the drain hole without needing to force high-pressure wands inside.
Dometic publishes a frequency for it: a full-time RVer flushes every 60 days, or every 30 days in the Southwest; a part-time RVer at least twice a year, or every 90 days in the Southwest. On a Suburban the same flush happens when the rod comes out, which is why the annual rod change and the annual flush are one job rather than two.
What the rod does not fix
A sacrificial anode rod has one job: to corrode so your steel tank doesn't. It is not an electrical part and it does not control water temperature. If your water heater won't ignite on gas, won't heat on electric, or runs out of hot water too fast, the anode rod has nothing to do with it. Those faults are covered in the RV water heater not heating guide.
Rotten-egg (sulfur) hot water is the one fault that does relate to the anode rod. If your water smells like sulfur, it usually means the anode rod is reacting heavily with sulfur-bearing water (especially aluminum alloy rods). Replacing a degraded rod or switching from aluminum to magnesium often clears the smell, though Dometic also recommends a vinegar flush for their aluminum tanks.
Where to go next
The water filter finder covers the other part of the fresh water system that gets changed on a schedule, and a pump that will not prime is the supply side of the same system. The parts page lists the rod and the tank as separate parts, with what fails on each. Fitting the rod is a job a mobile technician can do, and the directory finds one by state.
Sources
- Suburban, tank water heaters operation and maintenance guide, part 206244: the yearly replacement recommendation, the consumption or weight loss rule at 75 percent, higher wear on water with high iron or sulfate, the 1-1/16 inch socket, the pipe thread sealant for potable water, the warranty statement about operating without the anode, the sediment description, and the odor treatment
- Suburban, 2025 catalogue SUB-401.02: the porcelain-lined steel tank series, and the two extended life anode rods, 233514 in magnesium and 233516 in aluminum
- Suburban, replacement anode rod: the magnesium rod as the replacement for its tank water heaters, with the aluminum rod 233516 available as the alternative
- Dometic, L.P. gas water heater, 6 and 10 gallon XT models: the aluminum tank and its clad layer, the warning that replacing the drain plug with an anode rod damages the coupling, that aftermarket anode devices void the warranty, the flushing procedure and the flushing tool, the two quarts that stay in the tank, the 60 and 30 day full-time interval and the twice annual and 90 day part-time interval, and the vinegar treatment for hydrogen sulfide
- Dometic, L.P. gas water heater, 9 gallon gas and electric: the warning against anode rods and other non-approved devices
By OriginRV. Last reviewed on Nov 2, 2026.
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