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Do Rheem Water Heaters Have Anode Rods

To anode rod, or not to anode rod? That is the question. It’s a good question, and I am here to help you out. Anode rods are closely associated with water heaters, and with good reason. They make a massive difference to the life expectancy of your water heater.

As anode rods are important to water heaters, you would assume that all water heaters, including Rheem models, would have them. But Rheem has an exception to the rule. So, let’s get to the bottom of Rheem water heaters and anode rods.

Rheem water heaters have an anode rod to protect the metal storage tank unless they are plastic or tankless models. Aluminum and magnesium rods are popular, suitable choices for Rheem heaters, but some better fit specific water conditions. It’s relatively easy to find, detach, and replace the rod.

Rheem Tank-Type Heaters Have Anode Rods

Water heaters with metal storage tanks require anode rods as protection from the corrosive substances in the water. Anode rods are designed to interact with these substances preferentially and corrode in the place of the water heater storage tank.

Without the rod, that corrosion would be directed at the storage tank and will eventually cause it to leak or burst—an inconvenience and expense we all want to avoid.

Standard Rheem tank-type water heaters will need an anode rod; however, there is a model that is the exception. This is the Marathon model, which is made with a plastic tank and titanium elements.

Rheem Prestige High Efficiency 9.5GPM Indoor Natural Gas Tankless Water Heater

Titanium is highly unreactive, so it’s unaffected by the corrosive elements in the water. Furthermore, corrosion is the result of these elements reacting with the metal of a tank. Without the metal tank, you don’t get that same corrosion process, so the plastic tank jacket is also resistant to corrosion.

This means that no anode rod is needed in the Rheem Marathon water heater as there is nothing the rod needs to protect.

What Type of Anode Rod Do Rheem Heaters Use?

Anode rods come in several types of materials that are less noble elements than the tank metal and more readily react with oxygen and go through that oxidization and corrosion process.

  • Magnesium.
  • Aluminum.
  • Zinc.
  • Aluminum alloy.
  • Zinc alloy.

Magnesium and aluminum anode rods are the popular choices, but certain types are preferable depending on your water.

Aluminum rods work best with hard water, magnesium is the best choice to use with water softeners, and zinc rods (including the alloy versions) are the best for well water. If you are unsure what rod is best, taking a magnesium rod is a standard selection for any situation.

Rheem SP11309C R-Tech Resistor Magnesium Anode Rod with 44-Inch Length and 0.7-Inch Diameter
  • For best results, use only Rheem replacement parts for repairing your Rheem Water Heater
  • Anodic Material: Magnesium, Total Length (in.): 44-3/8, Rod Diameter (in.): 0.700, Hex Head Size (in.): 1-1/16
  • Thread Size - NPT (in.): 3/4, Resistored: Yes
  • Kits which contain this part: 45W363

Last update on 2023-05-28 / Affiliate links / Images from Amazon Product Advertising API

The size of the rod you need for your water heater depends on the size of the tank. You need a rod that can fit into your water tank. So, measure your tank (or check the specifications) to find the maximum size rod that you can buy.

Location of Anode Rod

The rod will be connected at the top of your water heater and generally runs centrally in the tank.

The head of the anode rod will be visible from the outside of the tank and is how you detach the rod. This should be located under a plastic cover.

So, if you look at the middle of the top part of your water heater, you should see the hex-shaped head of the anode rod. You can also always refer to the instruction or user manual if you need to.

Plumber hands hold old rusty heat element

Can You Replace Anode Rod on Rheem Water Heater?

Anode rods are meant to be installed, uninstalled, and replaced every few years. To replace an anode rod on a Rheem water heater, you need to follow a few steps:

  1. Shut off the power or gas (vacation mode) of the heater. Then the cold-water supply (relieve tank pressure by opening a hot water faucet).
  2. Drain some water from the tank (approximately 2 gallons).
  3. Expose the head of the rod and detach it with a wrench. There are a couple of tips for removing a seized rod.
  4. Install the new rod and tighten it. Use Teflon tape to make removal easier in future.
  5. Turn on a hot water tap in the house and re-open the cold-water supply for the heater. Let the tank refill. After about a minute, you can turn off the faucet and check for any leaks around the rod.
  6. Turn the gas or electricity supply back on.
  7. Check for leaks over the next day.

Tankless Rheem Water Heater Don’t Have Anode Rods

Tankless water heaters are designed for as-needed hot water supplies and don’t have metal tanks in which they hold and heat water. Without the tank that is susceptible to corrosion by the minerals in the water supply, there is no need for an anode rod. So, tankless water heaters will not have an anode rod. This is one of their many benefits.

Anode rods are supposed to circumvent the problem of water sitting in and against your water storage tank, where it can react with and corrode the metal. Tankless water heaters do not store water. They heat water on demand and directly from the water supply pipes and so do not have the problem of a corroding tank.


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