Water Heater Anode Rod Aluminum vs. Magnesium

Last Updated On October 19, 2021
Water Heater Anode Rod Aluminum vs. Magnesium

Do you need to purchase a replacement anode rod and want to know the difference between aluminum and magnesium anode rods? While most people prefer magnesium, it is important to understand how it differs from aluminum to decide what type of anode rod will work best for the water heater in your home. 

Both options prevent corrosion in the water heater tank, but they also have distinct advantages and disadvantages that you should know before buying a replacement anode rod. 

In this PlumbingNav guide, you will learn: 

  • Difference Between Aluminum and Magnesium Anode Rods
  • Best Anode Rod Material Type
  • Anode Rod Buying Guide
  • 5 Best Anode Rods

What's In This Guide?

      Quick Anode Rod Basics

      Both gas and electric water heaters contain an object called an anode rod that you place into the water heater tank to absorb corrosion in order to keep it away from the tank walls. 

      To make anode rods, manufacturers use stainless steel cable and wrap it with sacrificial metal that attracts corrosion. The most common sacrificial metals used to make anode rods are: 

      • Aluminum
      • Magnesium
      • Zinc

      However, as zinc anode rods refer to aluminum rods with small levels of zinc in them, we will stick to comparing aluminum and magnesium anode rods. 

      Top 4 Differences Between Aluminum and Magnesium Anode Rods

      Aluminum and magnesium anode rods both work to prolong the life of your water heater tank. But should you buy an aluminum anode rod or a magnesium anode rod? 

      Some of the things to consider include:

      • Initial Cost
      • Effectiveness
      • Longevity of Anode Rod
      • Longevity of Water Heater Tank
      • Water Quality

      1. Initial Cost

      Aluminum anode rods cost less than magnesium anode rods. A replacement anode rod generally costs between $20 – $50, with aluminum falling on the lower end of the spectrum and magnesium at the higher end. However, magnesium anode rods provide a better value.

      See this post if you need to know how to replace your water heater’s anode rod, step by step.

      2. Longevity of Anode Rod

      Aluminum anode rods last longer than magnesium anode rods since aluminum corrodes at a slower pace than magnesium. Visually inspect your anode rod once a year as part of your regular water heater maintenance plan and replace it every 3 to 5 years. 

      How do you know when to change your anode rod? 

      Most anode rods require replacement after 3 to 5 years. You want to change it before you notice discoloration in your water or a foul odor. To prolong the life of your anode rod, purchase a water softener, as hard water will expedite the deterioration of your anode rod. 

      3. Longevity of Water Heater Tank

      Aluminum anode rods may not have the high-level corrosive properties to keep up with the needs of your water heater, leading to faster corrosion and deterioration of the tank. 

      Magnesium anode rods protect against corrosion better, extending the life of your hot water tank. This makes magnesium anode rods more effective in the long run. 

      4. Water Quality and Your Health

      You want safe water to come from your water heater, especially if you plan on consuming it. The metal anode rod you put in it can significantly affect the water quality. 

      Magnesium anode rods reduce chlorine levels in the water, making it healthier to consume. Some studies even show additional health benefits from magnesium, so most health-conscious homeowners prefer magnesium water heater anode rods. 

      Magnesium anode rods can sometimes produce a rotten egg smell in the water. However, you can fix this quickly by replacing the anode rod. 

      Aluminum anode rods leave sediment deposits at the bottom of your water heater tank, and the sediment deposits can ruin the quality of the water that comes from it. 
      Also, high aluminum levels in the water can lead to health problems. In fact, secondary standards recommend an aluminum concentration of drinking water between .05 – .20 mg/L.

      Best Anode Rod Material (Aluminum vs. Magnesium)

      Ultimately, you will see better results when you purchase a magnesium anode rod when compared to aluminum.  

      Aluminum rods make an appropriate choice when you want to stick to a strict budget and don’t plan to consume the water. However, magnesium anode rods will provide better results in almost every other situation, even if you need to replace it more often. 

      Anode Rod Buying Guide

      Now you know the difference between aluminum and magnesium anode rods, but you still have a lot of products to choose from. Use this guide to buy the best anode rod for your water heater. 

      Things you need to consider include:

      • Water Characteristics
      • Anode Rod Placement 
      • Size of Tank
      • Accessories

      Water Characteristics

      Generally speaking, magnesium anode rods work best in homes with soft water. Hard water may deteriorate the anode rod more quickly. That’s why people with hard water may opt for aluminum anode rods that withstand the hard water better. However, a water softener can give you the opportunity to enjoy the benefits of a magnesium anode rod. 

      Magnesium anode rods make an especially good choice in areas with water with high alkalinity as they lower the levels of chlorine in the water. 

      Anode Rod Placement 

      You will attach most anode rods to the designated location on the top of the water heater tank, but some water tank models require you to replace them at the hot water outlet on the bottom of the tank. You need to buy the appropriate anode rod for your unit. 

      Height of Tank

      You want your anode rod to fit to the absolute bottom of your water heater for the best effects. Look in your water heater manual to get the proper height of your unit, or measure it yourself. 

      If you use an anode rod that is too short for your water heater, you will need to replace it more often. 

      Accessories 

      Some products will include accessories to help you replace the anode rod. The most common accessories are Teflon tape and a hex socket tool. If your product doesn’t come with these accessories, you will need to provide your own.

      did you know Water Heater Anode Rod Aluminum vs. Magnesium

      5 Best Aluminum and Magnesium Anode Rods

      We found some of the best anode rods available to help you narrow down your search. Check out the five best aluminum and magnesium anode rods. 

      1. Kelaro Magnesium Water Heater Anode Rod

      This magnesium water anode rod is 44” long and ¾” in diameter. It can fit in tight spaces with its flexible design, and it works with most major water heater brands. This product comes with one anode rod and does not include accessories. 

      2. Kohree Aluminum Zinc Anode Rod

      This non-toxic aluminum and zinc anode rod comes with one 44” anode rod as well as tape. It has a connection size of ¾”, which makes it compatible with most water heaters. It also comes hinged in four places to make it easy to work with. 

      3. The Water Connection AR109 Magnesium Anode Rod

      This magnesium anode rod provides protection for slightly taller water heaters at 48” long. It comes in one long rod as opposed to the other segmented options. You can choose between the 3” nipple or hex head design. 

      4.  The Water Connection AR136 Aluminum Zinc Anode Rod

      This product provides one solid 44” aluminum zinc anode rod with a ¾” hex head. It does not come with tape or any other accessories. 

      5. Blue Lighting Magnesium Anode Rod

      Blue Lightning offers this segmented, magnesium anode rod with standard measurements of 44” long and a diameter of ¾” with a hex head. They claim you can expect at least two years of corrosion protection with this product. 

      FAQ’s on Aluminum, Magnesium, and Zinc Anode Rods

      Which is better: magnesium or aluminum anode rod?

      Magnesium anode rods extend the life of your tank better than aluminum anode rods and offer significant health benefits, making them a much better value despite the higher price tag. 

      If you have especially hard water or budget concerns, an aluminum anode rod may suit your needs better. 

      What type of anode rod is best?

      Magnesium anode rods offer the best overall effectiveness. However, you may want to consider your other options, particularly a powered anode rod. 

      You can opt for a sacrificial anode rod or a powered anode from these four anode rod options:

      • Aluminum (sacrificial)
      • Magnesium (sacrificial)
      • Zinc (sacrificial)
      • Titanium (powered)

      A powered anode rod emits an electrical current to eliminate the corrosion inside of your water tank. It requires a bit of electricity, but it will not deteriorate nearly as quickly. It also keeps the water healthy, and it prevents the rotten egg smell. However, it costs substantially more than all of the other options. 

      What is better: zinc or magnesium anode rod?

      Zinc anode rods contain ten parts aluminum to one part zinc, making them extremely similar to aluminum anode rods. Magnesium anode rods will protect your water heater tank better than zinc anode rods, but zinc anode rods work well against rotten egg smell coming from your water heater. 

      Are aluminum anode rods dangerous?

      In most cases, aluminum anode rods will not cause you too much danger as long as you don’t drink the water. However, they come with a higher risk of health concerns than other options. 

      Not only do aluminum anode rods lead to sediment buildup, lowering the quality of the water, but they also can leak if not changed regularly and possibly lead to aluminum toxicity. 

      Some studies say an increased exposure to aluminum can lead to serious health concerns, but the risk from the aluminum anode rod in your water heater is low. 

      To reduce the risk from your aluminum anode rod:

      • Change the anode rod regularly
      • Do not drink water from the water heater
      • If you do drink the water, let it run for 8 seconds before filling your glass

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