In order to get as much use out of your water heater as possible, you’ll want to know how to maintain it properly. There are several factors influencing how long your water heater can survive, and there are ways you can make sure your heater survives longer.
Different types of water heaters last longer than others, but for the standard glass tank water heater, the presence of an anode rod makes all the difference. Anode rods replaced regularly can extend the life of your water heater up to twice as long.
The longevity of water heaters without anode rods is about: 5-8 years. The actual lifespan depends on water hardness, water heater type and quality, when the anode rod was removed, and how hot the water is. In extreme cases, the water heater may only last 3-5 years without an anode rod.
Average Lifespan of Water Heater Without Anode Rod
So many factors aside from the anode rod play a role in the longevity of a water heater (we discuss them shortly), so it is difficult to come up with an exact time frame. However, a good way to approach this and arrive at an estimation is to look at how long an anode rod lasts.
Anode rods are, by nature, more reactive than the metal of the water heater. However, they are also smaller and are completely corroded much faster than the tank would be. These two variables can be assumed to balance each other out more or less (but don’t take that assumption as law!).
Anode rods generally last up to 5 years, but they work best if replaced every 3 years.
So, a water heater with a regularly changed anode rod lasts 10-15 years. Water heaters last 8-10 years without having their anode rods replaced regularly. Without an anode rod at all, you can estimate the lifespan of your water heater to be between 5 and 8 years.
Many people are tempted to remove their anode rods to clear up the smelly rotten egg smell caused with well water. Instead, you should replace the rod with a zinc alloy rod, which doesn’t cause the same production of hydrogen sulphide gas.
As anode rods are far cheaper to replace every 5 years compared to a water heater, it is highly advisable to keep the anode rod!
Factors Affecting Rate of Water Heater Corrosion
The presence of an anode rod is by far the most influential factor when it comes to the rate of water heater corrosion, although it does not actually play a role in the day-to-day functioning of the heater. However, there are additional factors that play a role, and when you remove the anode rod, these factors come to the fore and exert a greater influence on the lifespan of the heater.
Hardness of the Water
One of these factors is the hardness of the water. Hard water is defined by its high concentration of calcium and magnesium. Hard water has benefits and drawbacks. It can be good for drinking due to the health benefits of calcium and magnesium, but it decreases the efficiency of water for cleaning.
Moreover, and more to the point for the purposes of this article, hard water is damaging to water heaters as the minerals build up inside the heater over time. The build-up:
- Reduces the efficiency of the water heater when it covers the heating elements.
- Can clog and damage pipes as chunks of hard mineral break off from the body of the tank.
- Compromises the integrity of the water heater tank lining, making it even more vulnerable to corrosion and leaks.
3 Ways to Combat Hard Water
1. Reduce the Temperature of the Water
Heat increases the speed at which minerals separate from water and create deposits, so one way to help a water heater with hard water is to decrease the temperature. While this will slow down the speed of mineral build-up, it will not stop it.
2. Regular Maintenance
Another method is to flush the water heater regularly to remove the regular build up of minerals.
3. Water Softeners
Water softeners can be installed to treat hard water before it gets to the heater, thereby reducing limescale and increasing the life of the heater.
However, it is a bit of a catch-22 situation because water softeners use ions such as sodium or potassium to replace the magnesium and calcium. These ions are more metal-reactive. So, your limescale build-up will be reduced and the quality of your water will improve, but the risk and rate of corrosion in the tank becomes greater.
With an anode rod, this simply means more regular replacement of the rod. Without the rod, it means rapid deterioration of the water heater itself.
Water Heater Type and Quality
Water heaters come in a variety of materials, and their warranties are a good estimate of their lifespans. Most water heaters have lifespans of about 10-15 years, but with the right maintenance and good water quality, some can last for over 20 years.
Typically, electric-powered water heaters will last longer than gas-powered water heaters as well.
Most water heaters are steel with a fiberglass-lined tank on the inside. These tanks need anode rods to fight corrosion because the fiberglass lining is never perfect and is also susceptible to being cracked or damaged.
Not all water heaters are made to the same standard. Some use low-quality materials or are constructed poorly. These will not last as long in comparison to higher-quality heaters, with or without the anode rod.
Some Water Heaters Don’t Need Anode Rods
Stainless steel tanks are of higher quality and resist rust and corrosion, meaning they do not require anode rods. They are more expensive for this reason.
You can find a comprehensive comparison of stainless steel and glass-lined water heaters here.
Water heaters come in tankless varieties as well, and these come with a longer lifespan of about 20-30 years. While tankless models don’t have sitting water inside them, and therefore do not require an anode rod, they are still in some danger of rust and corrosion unless properly maintained.
When Was the Anode Rod Removed?
When you remove your anode rod affects how fast the heater will corrode without one. If the rod is removed when the heater is older, then the lifespan of the heater without the rod will be shorter still because it has already suffered some deterioration simply due to age.
If the rod is removed while the heater is not very old, it will have a longer lifespan without the rod. However, this is still shorter than the lifespan with a rod. It is advisable to replace the anode rod once removed to extend the life of the heater as much as possible.
How Hot Is the Water?
Hot water can speed up the process of corrosion and mineral build-up. As mentioned previously, heat increases the damage caused by hard water on the tank of the water heater since it accelerates the speed of mineral deposit formation. Similarly, heat acts as a catalyst to speed up the rate of corrosion of the steel parts of the water heater.
The common default temperature of many water heaters is 140 °F, but the Department of Energy recommends 120 °F for safety. This adjustment is also beneficial for decreasing corrosion of the water heater.
Anything below 120 °F should be avoided as it may increase the risk of bacteria accumulating inside the water heater tank.
You can change the temperature of the water with the dial on your heater. To assess the heat of the tap water, you can run your water on hot for three minutes, then adjust the temperature according to what you feel. You can then run on hot for three more minutes to see if the new temperature is acceptable.