How To Prevent Water Heater Corrosion With These Proven Tips

Water heater corrosion is a critical issue for homeowners and users of hot water systems. It occurs when metal parts of the heater deteriorate over time due to chemical reactions with water and surrounding elements.

If left unaddressed, corrosion can lead to reduced efficiency, higher energy bills, poor water quality, and serious safety risks like leaks or tank ruptures.

In this guide, we’ll explain the causes and signs of corrosion, along with effective prevention and repair strategies.

By understanding these key factors, you can protect your water heater, extend its lifespan, and avoid costly or dangerous problems.

Water Heater Corrosion And What You Need To Know

What is Corrosion?

Corrosion is a process in which metal deteriorates due to a chemical reaction with its surrounding environment. This phenomenon can also occur in nonmetals. For more detailed information refer to this wiki article.

What is Rust?

Rust forms when metal containing iron undergoes corrosion, leading to the creation of iron oxide in the presence of oxygen and moisture. This process results in a recognizable reddish-brown crust.

Types of Corrosion

There are different types of corrosion, and the following two are the most common in plumbing and water heating systems. While this issue most often affects older water heaters and piping, it can also occur in new installations.

Galvanic or Electrolytic Corrosion

Galvanic or electrolytic corrosion occurs when two different materials are in contact via an electrolyte. A typical example is the water heater, where the anode rod is made of magnesium, a water tank is made of steel, while the electrolyte is water. In this case, the deterioration occurs as the molecules of one material are drawn toward the molecules of the other material, resulting in a chemical reaction – corrosion.

This is why an anode rod is called a sacrificial rod, and its rate of depletion is increased as the water becomes hotter or acidic. As the water tank is made of steel and acts as the cathode, the anode rod had to be made of the material which can be attacked first protecting the metal tank – so zinc, aluminum, and magnesium are found to be the best options for the anodes.

Atmospheric Corrosion

Atmospheric corrosion, also known as oxidation, is caused by the moisture and gases found in the air. For example, ferrous metals, such as iron, when exposed to the air, form iron oxide or, as we know it – rust. Every molecule is affected by this reaction until the metal rusts away completely. Non-ferrous materials are not affected by this process in this case.

Importance Of Understanding Water Heater Corrosion And Potential Consequences

Understanding water heater corrosion is of utmost importance for several reasons, as it can lead to significant potential consequences:

• Safety concerns: Corrosion can weaken the structural integrity of the water heater tank, increasing the risk of leaks or tank rupture. This can result in water damage to your property, potential injuries, and even the release of scalding hot water.
• Increased costs: Corrosion can significantly reduce the lifespan and efficiency of your water heater. A corroded water heater requires more energy to heat water, leading to increased energy bills. Additionally, corrosion-related repairs or the need for a premature replacement can be costly.
• Water quality issues: Corrosion in the water heater can lead to the contamination of your hot water supply. Rust and other corrosive byproducts may discolor the water, give it a foul odor, or impact its taste. This can be unpleasant for daily use and affect activities such as bathing, cooking, and washing dishes.
• Reduced efficiency and performance: Corrosion inside the water heater tank can result in sediment buildup, reducing the available space for water and hindering heat transfer. This leads to decreased efficiency and longer heating times, causing delays in obtaining hot water and wasting energy.
• Environmental impact: A corroded water heater that leaks or requires replacement contributes to unnecessary waste and environmental impact.

Causes Of Water Heater Corrosion

Water heater corrosion can occur due to various common causes that homeowners should be aware of. These causes include:

• Water chemistry: The chemical composition of water can play a significant role in causing corrosion. Hard water, which contains high levels of minerals such as calcium and magnesium, can accelerate degradation within the water heater tank. Additionally, water with high acidity or low pH levels can be corrosive and lead to the deterioration of metal components.
• Sediment accumulation: Sediment, including minerals and debris present in the water supply, can settle at the bottom of the water heater tank over time. This sediment acts as a barrier between the water and the tank lining, promoting corrosion in the exposed areas.
• Elevated water temperature: Higher water temperatures can expedite the corrosion process within the water heater tank. Hot water increases the rate of chemical reactions, leading to more rapid erosion of the metal surfaces.
• Oxygen exposure: Oxygen in the water and surrounding air can react with the metal components of the water heater, resulting in corrosion. Oxygenated water tends to corrode the tank and other metallic parts more quickly, especially when combined with other corrosive factors.
• Poor anode rod condition: Magnesium, zinc, and aluminum anode rods are sacrificial metal rods inserted into the water heater tank to attract corrosive elements and protect the tank lining. Over time, these anode rods can become depleted or deteriorated, leaving the tank more vulnerable to damages.
• Manufacturing defects or poor quality materials: In some cases, water heater corrosion may result from manufacturing defects or the use of low-quality materials during production. Poorly designed or constructed water heaters can be more prone to corrosion-related issues.
• Dissimilarity of the metals that are connected: The dissimilarity of the metals that are connected can lead to corrosion through a process called galvanic corrosion. When two different metals come into contact in the presence of an electrolyte (such as water), one metal becomes the anode and the other becomes the cathode. The more reactive metal (the anode) corrodes faster, while the less reactive metal (the cathode) remains protected. This electrochemical reaction accelerates corrosion, leading to the degradation of the metal that is more prone to rusting or wearing away.

The Importance Of Water Quality And What It Means For My Water Heater

For most of us with a hot water tank heater in our homes, whether gas, oil, or electric, the quality of the water supply is a significant concern. While municipal water systems are typically safe to consume, they still contain minerals that can cause damage to our devices, including water heaters, from the inside out.

Regular checking and maintenance are crucial for your water heater, and most DIYers can easily perform these tasks. However, if your freshwater source is a well, the water problem can be particularly severe. Well water often contains higher levels of solids, which can pose complications if they find their way into your water heater.

According to the EPA, over 13 million households in the US rely on private wells for their water supply without regulatory oversight. As a private well owner, it becomes your responsibility to ensure the safety of your water supply. Without an inline filter on your water supply, sediment gradually accumulates in your water heater, causing potential damage.

The accumulation of contaminants, which are often heavy, settles at the bottom of your water tank, forming a thick layer. In gas or oil-fired heating devices, the burner sits directly beneath the base. When it is activated to heat your water, it has to struggle through the layer of sludge. This results in increased energy usage and the burner working at maximum capacity to bring the water to the desired temperature. Consequently, this excessive heat can cause your pressure relief valve to open up and leak.

Signs And Symptoms Of Water Heater Corrosion

There are several signs and symptoms that can indicate water heater corrosion:

• Discolored water: If you notice rusty or discolored water coming from your hot water taps, it could be a sign of water heater corrosion. The presence of rust or sediment in the water indicates that the inner lining of the water heater tank may be deteriorating.
• Foul odor or strange taste: Corrosion within the water heater can lead to a foul odor or metallic taste in the hot water supply. This is often caused by the presence of rust or other corrosive byproducts in the water.
• Fluctuating water temperature: Corrosion and sediment buildup can interfere with the water heater’s ability to maintain a consistent temperature. If you experience fluctuating hot water temperatures or find that the water takes longer to heat up, it may be due to corrosion affecting the heating elements or obstructing heat transfer.
• Leaks or water damage: Corrosion weakens the structural integrity of the water heater tank, making it more prone to leaks. If you notice water pooling around the base of the water heater or signs of water damage in the surrounding area, it could indicate corrosion-related issues.
• Unusual sounds: Corrosion can cause sediment to accumulate at the bottom of the water heater tank, leading to popping, cracking, or rumbling sounds during the heating process. These noises indicate that the sediment is interfering with the water heater’s efficiency.
• Reduced efficiency and increased energy bills: If your water heater becomes corroded, it will require more energy to heat water effectively. This can result in reduced efficiency and higher energy bills.

Prevention, Maintenance, And Troubleshooting

Prevention and maintenance are crucial for ensuring the longevity and optimal performance of your water heater. Here are some key preventive measures and maintenance tasks to consider:

1. Regular inspections: Schedule regular inspections of your water heater to check for any signs of corrosion, leaks, or other issues. Look for rust, discoloration, or unusual noises during operation.
2. Anode rod replacement: The anode rod is a sacrificial metal rod inserted into the water heater tank to attract corrosive elements and protect the tank lining. Over time, the anode rod becomes depleted or corroded and needs to be replaced.
3. Flushing the tank: Sediment buildup inside the water heater tank can accelerate corrosion and reduce efficiency. Regularly flushing the tank helps remove sediment and prolongs the life of the water heater.
4. Water softening: If your water supply is high in mineral content, consider installing a water softener to reduce the hardness of the water. Softening the water helps minimize scale and sediment buildup, which can contribute to corrosion.
5. Temperature and pressure relief valve testing: The temperature and pressure relief valve is a safety device that releases excess pressure from the water heater tank. Test this valve periodically to ensure it is functioning correctly and has not become stuck or corroded.
6. Water quality testing: Have your water quality tested regularly to identify any potential issues that could contribute to water heater corrosion. Testing can reveal the presence of high mineral content, acidity, or other impurities in the water supply.
7. Professional maintenance: Consider hiring a professional plumber or technician to perform regular maintenance on your water heater. They can perform tasks such as cleaning and inspecting the tank, adjusting temperature settings, and ensuring all components are functioning properly.

In severe cases where the corrosion has extensively damaged the tank or compromised its structural integrity, replacing the water heater tank may be necessary. Consult with a professional to determine the best course of action based on the extent of the corrosion and the overall condition of the water heater.

Tankless and Corrosion

In a case of the tankless water heaters, corrosion can also occur, but rarely, because water gets in contact with the heater’s components only in a short period, plus the heat exchangers are made of copper and stainless steel. Since the heat exchanger stores only a small amount of water, this is where the corrosion might happen. The advantage of the tankless models is that their parts can be easily replaced if corroded.

Plumbing Corrosion

All the metal pipes that are used in plumbing can corrode at a certain point. Even stainless steel and copper piping can corrode.

Galvanized pipes, for example, first corrode at the threads while copper pipes rust at the connection with the steel pipe, piping hanger, or similar elements. If there is a need to connect copper and galvanized pipes, use dielectric connectors, keeping the elements with different materials away from contacting each other. The problem with the galvanic action can often be noticed around the water inlet and outlet when the installer is not using the dielectric connectors.

Today’s new homes are mainly built with non-corrosive material (plastic), while in old houses, where the galvanized pipes are still present, or homes with wells, corrosion happens more often.

Copper pipe can also corrode, and corrosion is recognized by the blue-green stains on the pipes, tub, sink, and shower drains.

Conclusion

Taking proactive measures to prevent water heater corrosion and implementing regular maintenance and monitoring practices are key to ensuring a longer lifespan for your water heater. By addressing potential causes of corrosion, such as sediment buildup and water quality issues, you can significantly reduce the risk of damage and costly repairs.

Regular maintenance, including flushing the tank, replacing the anode rod, and testing safety valves, helps to keep your water heater in optimal condition. By staying vigilant and addressing any signs of corrosion or leaks promptly, you can prevent further damage and extend the lifespan of your water heater.

Remember, the importance of water heater maintenance goes beyond just saving money and avoiding inconveniences. It also ensures the safety of your home and its occupants, maintains water quality for daily use, and minimizes the environmental impact associated with premature replacements.

By prioritizing preventive measures and regular maintenance, you can enjoy the benefits of a reliable and efficient water heater for years to come. Don’t underestimate the significance of these actions in preserving the performance and longevity of your water heater.