Have you ever used warm or hot water from your faucet to cook your food? Or to heat up for tea or other drinks? If you are like me you have. I always thought that if I used hot water from the faucet then the pan/teapot would heat faster and I love "faster".   Little did I realize (until I was doing some water heater repair) that inside my hot water heater is something called an Anode Rod.  WHAT IS AN ANODE ROD ???

Well .... Water rusts and corrodes metal, and your water heater would be a crumbling mess without a small rod inserted into the top of the tank. This rod is called an anode rod (or sometimes a sacrificial anode rod) and it is the only reason your water heater hasn’t left you bathing in rusty water.

THE PROBLEM:

This rod is made out of either Magnesium or Aluminum. WHAT? ALUMINUM? That was my response. Having studied Natural Health I remembered that Aluminum is linked to Alzheimers, Kidney Disease and Cancer. 

According to  the Division of Toxicology and Environmental Medicine September 2008 

"Brain and bone disease caused by high levels of aluminum in the body have been seen in children with kidney disease. Bone disease has also been seen in children taking some medicines containing aluminum. In these children, the bone damage is caused by aluminum in the stomach preventing the absorption of phosphate, a chemical compound required for healthy bones."

"Oral exposure to aluminum is usually not harmful. Some studies show that people exposed to high levels of aluminum may develop Alzheimer’s disease, but other studies have not found this to be true. We do not know for certain that aluminum causes Alzheimer’s disease. " ( I don't know about you but I think ...Do I really want to take the chance?)

"Some people who have kidney disease store a lot of aluminum in their bodies. The kidney disease causes less aluminum to be removed from the body in the urine. Sometimes, these people developed bone or brain diseases that doctors think were caused by the excess aluminum. Although aluminum-containing over the counter oral products are considered safe in healthy individuals at recommended doses, some adverse effects have been observed following long-term use in some individuals."

Rust, or corrosion of metal, happens with three things: iron (or steel), oxygen and water. These are all plentiful in a water heater tank.  Although in modern water heaters the tank is encased in a thin layer of glass, water can still get into cracks and rust the water heater’s tank. So, water heater manufacturers place an anode rod into the tank.  An anode rod is made up of magnesium or aluminum. Both magnesium and aluminum are less-noble metals, meaning they corrode quickly in water. Let’s put on our chemistry hats and explore this a bit further.

The chemical reaction for rusting begins by oxidation, which is when iron loses two of its electrons to the oxygen found in the tank. When you place a magnesium or aluminum rod into water, this also occurs, just much faster. The bonds between the molecules of magnesium and aluminum give up their electrons faster than the bonds in steel or iron. Thus, when you place an aluminum or magnesium anode rod into a iron or steel tank of water, the oxygen in the equation takes the two electrons of the anode rod instead of the tank, as they gave them up quicker. This will rust the anode rod, but not the tank itself.

A simplistic answer to this question is that the anode rod corrodes faster than the iron or steel of a tank, making it so the tank doesn’t rust until the metal of the anode rod is completely corroded away.

YOU ARE ACTUALLY DRINKING THE CORRODED ALUMINUM IF YOU USE HOT WATER FROM YOUR FAUCET!

How Long does an Anode Rod Work?

Unfortunately, a sacrificial anode rod is called that for a reason. It is sacrificing itself to save the lining of the tank. At some point, all of the magnesium or aluminum of the rod will have corroded away, and it will no longer have electrons to give up to save the tank’s electrons from the rusting process. When the anode rod has corroded away, the water heater’s tank may begin to rust, which will cause the water heater to fail – and you’ll end up paying hundreds for a brand new water heater. That’s why it’s important to replace, or at least check, your anode rod every three years. Look at your manufacture’s recommendations to see when your particular water heater needs an anode rod change. If you have a home warranty protecting your water heater and other systems and appliances within your home, it’s important to note that a home warranty will not cover a water heater that rusted if the anode rod had not been properly maintained. However, if the water heater fails from normal wear and tear, a home appliance warranty should help cover it. 

REMEMBER:

Aluminum is also found in many other products such as pots and pans, anti-perspirants, some vaccines, baking powder, soda cans, aluminum foil and even some foods. It can never hurt to remove your exposure to aluminum as much as possible to help keep you safe and healthy.

References:
http://www.atsdr.cdc.gov/toxprofiles/tp22-c1-b.pdf 
http://www.webmd.com/skin-problems-and-treatments/features/antiperspirant-facts-safety?page=4