White residue on top of your water heater is the buildup of minerals, usually due to hard water. This white residue is also known as scale and consists mainly of calcium and magnesium.
What Causes White Residue On Top Of My Water Heater?
Hard water is the culprit behind white residue formation or scaling. This water has a lot of minerals like calcium and magnesium. As the water heats and evaporates, minerals and impurities settle on your water heater tank’s surface.
You will not notice their formation right away, but the white residue will be more evident with time. When the deposits build up, they interfere with your water heater’s functionality, such as heat transfer, and may even cause a complete heating system failure.
Scale reduces your water heater’s lifespan, so it is best to act on it to avoid further damage.
How Do I Tell If My Water Heater Is Scaling?
The first sign of fault within your water heater is the sound it produces. When there is build-up within your water heater’s tank or pipes, the sound will be off. A regular water heater makes a slow humming sound. Alarming sounds could either be crackling, banging, or popping.
When you hear these sounds, the mineral deposits have most likely settled within your water tank and are disrupted by the burners heating your water, hence the sounds.
How Do I Treat And Prevent White Residue In My Water Heater?
Flush your water heater to remove the mineral particles within your water heater before they harden and attach to the surfaces. Do this at least two to three times a year to effectively get rid of the scale.
Turn off your water heater, connect the drain outlet to a hose and drain out the water. Refill the tank and repeat the process until the water is clear of discoloration and particles.
Temperature also causes scale build-up as the evaporation process leads to the deposit of minerals and impurities in your water. The hotter the water, the more the minerals evaporate and solidify on your water tank’s surface.
Set your water heater temperature to 120 degrees Farenhight, which is hot enough to serve your purpose without risking scaling on your heater.
The most reliable scale build-up prevention is the use of a water softener. Water softeners remove the elements that make water hard, such as calcium and magnesium, preventing white residue and scale from forming even as water evaporates.
Are Corrosion And Scaling The Same?
Corrosion and scaling are different. While scaling results from mineral deposits formed by the evaporation of hard water, corrosion results from water, metal, and oxygen reaction. Instead of white residue, corrosion develops a product known as rust.
What Causes Corrosion On Top Of My Water Heater?
The most common reason there is corrosion on top of your water heater is that oxygen and carbon dioxide reacts with water and eat away at your metal tank.
If the top of your water heater gets heated the most, you may not notice a lot of corrosion there. The heat accelerates the reaction between metals and water, so certain parts of your heater may corrode more than others.
Many components make up your water heater. These components, such as the pipe connections and valves, are metallic. Most of them are at the top of your water heater.
Galvanic corrosion is responsible for corrosion in most water heaters. It occurs when two different metals connect at a point and react in the presence of water. As water constantly flows through them, they end up rusting due to oxygen within the tank. In severe cases, the metals may rust, dissolve and cause your water heater to leak eventually.
In other cases, the components within your water tank may cause or accelerate corrosion. A faulty sacrificial anode rod can cause corrosion. Gases and minerals in your water make your water tank corrode fast. The sacrificial anode rod attracts these gases and minerals, diverting corrosion from your tank to the rod itself.
If your sacrificial anode rod is worn out, it will no longer attract minerals and gases, and these elements will corrode your water tank.
The temperature-pressure release valve within your heater has another function besides releasing water and decreasing pressure in your water tank. It also prevents air from getting in your water heater tank. If the valve is faulty, loose, or broken, air, including oxygen, will enter your water tank and cause corrosion.
Most water heaters have glass linings to protect the heater’s interiors. If the lining wears out, the water heater will be exposed and will eventually experience corrosion.
How To Tell If There Is Corrosion On My Water Heater?
Inspecting your water heater is not the first thing that comes to mind when you think about home maintenance. Most water heaters are located in basements or attics, so they are not thought of as much.
The first sign that may tell that your water heater has corrosion is low or no water pressure. This is due to leaking that has occurred at the corrosion site on your water heater. If your water heater is within sight, you will notice water around the heater, indicating that it is leaking. You can call your plumber to identify the corroded area.
Water discoloration is also a red flag that your water heater has corrosion. The water may appear cloudy, brown, red, or orange. In some instances, you may notice small metal particles in the water. The discoloration and metal particles indicate corrosion and must be addressed, especially if it is drinking water.
Sometimes the water may be clear, but you realize the taste is weird. While the unusual taste could result from something else, corrosion is also suspect, so you best call a professional to inspect your water heater.
How Do I Treat Water Heater Corrosion?
Identifying points of water corrosion within your water tank will determine the course of action to treat it.
Your plumber may notice the point of corrosion, such as a rusting valve, remove it, and replace it before galvanic corrosion occurs.
Severe forms of corrosion are untreatable. Once there is discoloration and a difference in taste in your water, the corrosion has reached a dangerous level. You will have to replace the water heater as this form of corrosion is irreversible.
How Do I Prevent Water Heater Corrosion?
Seeing as extreme levels of corrosion are untreatable, and it is expensive to replace the water heater entirely, the best thing to do is prevent corrosion.
Get a plumber to check your water heater for signs of corrosion regularly. While you may notice some symptoms, such as leaking, a professional will know how to run corrosion diagnostics and treat the problem before it worsens.
You may also flush your water tank to clear out rust that may be at the bottom. Turn off your heater and attach a hose to its drain outlet. Run the water repeatedly by filling the tank and draining it out at least five times.
Flushing your tank ensures rust does not settle within your tank and no further corrosion.
Sources
https://homeguides.sfgate.com/prevent-scale-buildup-hot-water-heater-heating-element-63065.html
https://www.relianceplumbing.com/blog/water-heater-service/scaling-mean-for-water-heater/
https://www.researchgate.net/post/How-to-differentiate-the-product-of-corrosion-and-scaling
https://homeguides.sfgate.com/remove-rust-water-heater-64432.html