5 Reasons Why Your Water Heater Is Corroding

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Household appliances that are constantly exposed to water are more likely to rust. If you have invested in a quality water heater, you likely do not want to have to engage water heater replacement services anytime soon. Therefore, you should be aware of the signs and causes of water heater corrosion. This will help you take the necessary precautions to prevent corrosion to the best of your ability.

Causes Of Water Heater Corrosion

Defective Sacrificial Anode Rod

The air and carbonic acid from the atmosphere dissolves easily in water, causing it to be corrosive. To prevent damage to the tank and other components, water heaters usually have a magnesium, aluminum anode rod installed. The anode rod reacts to the corrosive elements instead of the rest of the water heater, thus protecting it. The anode rod can wear out over time, causing the water heater to start getting corroded. This is one of the signs of a faulty water heater.

Poor Plumbing


When the water heater installation is shoddy, there will be improper water pipe connections. This introduces air into the tank, which causes corrosion and damage to the internal linings of the tank. This highlights the importance of proper water heater installation, and serves as one of the reasons to hire a professional to install your water heaters.

Worn Out Glass Lining

Constant fluctuations in temperature from heating, as well as the accumulation of sediment, can cause cracks. This allows water to penetrate the lining and corrode the walls, leading to the formation of rust.

However, water heaters like the Rheem Xwell XS-20 Slim Classic Plus Electric Storage Water Heater have a glass or enamel lining to prevent corrosion of the metal water tank.

Signs of Water Heater Corrosion

Rusty Water


The hot water dispensed from a new water heater is clear. When one or more components of the water heater is rusted, however, the rust mixes with the hot water. You can see it immediately as an orange, reddish, or even brown discharge. This is one of the reasons to buy a good quality 707 water heater, as they boast their corrosion-resistant tanks.

Rusty Valves

If you see a ring of rust near the valve, it is a clear sign that one or more parts of the water heater is corroded. If left untreated, the valve can fail, which can lead to disastrous consequences. Regular checking is an important part of water heater safety.

Some heaters, like the 707 Compact Instant Water Heater, comes installed with a pressure relief device that vents the built-up pressure to prevent explosion.

Water Heater Leaks


Rust and corrosion wear out the internal walls of the water heater. This increases the likelihood of it springing a leak. The potential risks of a leaking water heater should not be neglected. If you have an instant water heater, reading up about the causes of instant water heater leaks is helpful in protecting against these harmful risks.

Why Should You Replace Your Corroded Water Heater?

Corrosion damage is typically irreversible for a water heater. Consequences of neglect would include health complications, safety hazards, or structural damage. Hence, when you observe any signs of water heater corrosion, it is likely also when you should replace your water heater.


To summarize, a water heater corrodes over time, due to failing anode rods, poor plumbing, or deterioration of the inner linings. This results in rusty water, defective valves, leaks – which may accumulate to bigger problems down the road. To protect yourself, you should replace your corroded water heater as soon as possible. You can find more information on what model to choose by referring to our storage heater buying guide or instant heater buying guide.

Water Heater City Singapore is your trusted partner for comprehensive water heater services. With over a decade of experience, we pride ourselves on being a reliable water heater company. Our services such as water heater installation/replacement including instant water heater services installation and storage water heater installations are done efficiently by our expert team. Moreover, we will ensure your storage water heaters are Licensed Installation with PUB Submission and all works comply with standards prescribed/stipulated by PUB. If required, we are also able to open a false ceiling, patch it back up, and paint it to restore it to its original condition. 

We supply a wide selection of water heaters from top brands like Ariston, Rheem, Joven, 707, Rubine, and Champs. With a proven track record of successful past projects and a number of positive customer reviews on Google and Facebook, we ensure every service we provide will be done efficiently and with the utmost attention to detail. Contact us on WhatsApp at +65 8241 0032 for transparent quotations and honest pricing for all your water heater needs!