WATER HEATER "101"

CAUSES OF FAILURE

Almost all components on a water heater can be fixed or replaced

except  for the tank. Once the tank rusts through, there is no way to repair it, replacement is the only solution. 

All water heaters come with a internal sacrificial "anode rod"

to protect against rusting.  An anode's sole purpose is to corrode away

instead of the steel tank.  Replacing the "anode rod" every two years

(more frequently if water is softened) will ad considerable life to a water heater at a fraction of the replacement cost.

WHAT EXACTLY IS AN ANODE ROD ?

The sacrificial anode is a metal rod usually made from magnesium

which helps prevent corrosion of the metal of the tank. 

Electrolysis eats away the metal anode instead of the metal of the tank.

Once the anode is gone the tank itself begins to corrode.

To prolong the life of your tank, make sure your anode rod is still intact,

and replace it when needed. If it has been longer than two years chances are extremely likely that the anode rod has corroded away and the corrosion 

process has set in on the tank itself.

The anode is screwed into the top of the tank and can be replaced.

Sometimes the anode is built into a special outlet fitting.

Water Softeners will cause the Magnesium anode rod to wear out more quickly, as the chemistry of the water is drastically changed.

Soft water is extremely aggressive and will eat through a magnesium 

anode rod aggressively within one years time.

MOST ALL Water heater manufacturers use magnesium anode rods as

opposed to aluminum to cut the cost in manufacturing,

the tanks and controls for the most part are ALL the same and made by

the exact same sub contracted companies,  and are universal.

If you find a water heater with an extended warranty for example twelve years, as opposed to six. You have undoubtedly found a water heater whose only difference is that it has an aluminum anode rod as opposed to a magnesium one... Another difference of course will about double the cost of the latter...

One Last  thought to consider is this......

Bacteria can react with magnesium anodes causing hydrogen sulfide which can cause "rotten egg odor". Experts state that this odor is completely harmless however the smell is somewhat undesirable.

Switching to an aluminum anode rod and flushing the water heater with a

mild household bleach solution will help to remove this odor.