"Robert A. Barr" Not.for.@harvest wrote
I installed a brand new GE (Rheem) electric water heater about 4
months
ago. Recently I've noticed a slight (but strengthening) smell of
sulfur
when I run hot water anywhere in the house.

Years ago, I had a problem with a really strong sulfur smell from the
hot water, and it turned out to be the sacrificial anode. Could that
be
the problem already?

Here's a partial copy of a water treatment article and some additions
I've made to it that I saved from a few years ago. It explains the cause
of hot water only odor.

If there is no cold water odor, and there can be although you don't
smell it in the house without spraying water under force into a large
bucket while smelling for the odor, sulfate is present in the water. A
magnesium anode rod (or what's left of one) is in the heater and a
sulfate reducing bacteria is present in the water. This bacteria takes
the oxygen off of the sulfate, making it sulfur. Reducing types of
bacteria are nonharmful.

The anode rod generates free hydrogen in water.

The hydrogen and sulfur together produces the smell.

Removing the anode rod altogether will remove one part of the equation,
eliminating the smell. Replacing the rod with one of different material
may also solve the problem. But if any of the rod falls off into the
tank as you remove a rod, it's the same as not removing or replacing the
rod. Removing the rod voids the heater warranty. Raising the temp to 140
deg f will also (usually) prevent the odor by killing the bacteria. Most
hot water manufacturers also have a different type of anode rod
available that does not generate the hydrogen - you would have to call
them and see what is available.

Cleaning the hot water heater with a heavy chlorine rinse eliminates the
bacteria and produces a temporary relief. Temporary can range from a few
days to months. Draining and then flushing the heater as part of this
sanitizing is always a good idea.

To quote Wes McGowan, excerpt taken from Water Processing for Home, Farm
and
Business 1988:

When a hydrogen sulfide odor occurs in a treated water (softened or
filtered), when no H2S is detected in the raw water, it usually
indicates the presence of some form of sulfate-reducing bacteria in the
system. These anaerobic, single-cell bacteria (Thisbacilles) can exist
in the piping system in the hone, especially on the hot water side. It
is most noticeable on the first hot water drawn in the morning. Water
softeners provide a convenient harbor and environment for anaerobic
(oxygen depleted) bacterial growth.

Sulfate bacteria can derive energy by reducing the sulfate ion in the
water to H2S, and produce by-product bicarbonate in the process. Organic
matter needs to be present for the bacteria to survive. However, the
concentration of organics in the raw water is often below detectable
levels. When this condition of H2S in hot water arises, the initial task
is to heavily chlorinate the entire piping system including storage and
hot water tanks.
Usually, a dose of household bleach left standing in the piping system
(hot and cold) overnight will destroy the sulfur bacteria. I has also
been reported from the field that after water softeners are installed,
the hot water will develop traces of H2S odor. Where softened water is
fed to certain hot water heaters, this condition has been overcome by
removing the anode element from the heater.

Gary
Quality Water Associates