We empty the water heater after every trip to stop the stink.
Remember the movie Young Frankenstein when Gene Wlder jumps back and exclaims : “ IT’s Alive !” The next time you pull a snot covered anode rod or get “curds” from your water heater remember that movie scene. The white snotty slime is sulfur bacteria and it is alive. It formed when the hot water cooled off enough to promote growth and it grew a bacteria colony which is in your water heater and clinging to the rod. It is not an inanimate crystalline structure (calcium or rod material) it is a carbon based living organism. This sulfur bacteria is normally the source of hydrogen sulfide (H2S) gas which smells like rotten eggs. When the colony is permitted to air dry and the water leaves the bacteria ,it dies, leaving behind a residue the color of the colony - see below.
Sulfur bacteria are also a host bacteria. This means it can be the starting culture for other bacteria’s such as iron. Bacterial slime may be white, grey, black or reddish brown if associated with iron bacteria. You will still get the rotten egg smell regardless of type. It has been stated these are harmless bacteria’s. However, if they formed from cross contamination (sewer waste) then they can be deadly. This is why we need to be “clean freaks” while filling and dumping to prevent cross contamination.
Water supplies (wells) sometimes have sulfites in them. If this is the case the water heater sacrificial anode rod (usually made out of magnesium metal) will supply electrons to the sulfites and create H2S. However, when this is the case the slime or curds will not be present in most cases. This is because this is actually a chemical reaction - not the birth or growth of an organism. In addition the H2S smell usually permeates ‘ALL’ the water and smells from well to tap. The sulfites present in the well usually react with metals (electrons) present in the water while it is still in the well. Hence, the rotten egg smell will be present in the RV fresh water tank as well as the water heater. This can be easily observed by getting your nose close to the cold water outlet. Turn it on, if it stinks with first water out - sulfites are in the RV fresh water tank usually from the supply. Sulfites in wells are usually documented to a region on locale. It is highly unlikely that every well you fill your RV or boat from has sulfites in it. Rather, you have live bacteria as stated.
Elevated temperatures above 160 F (71C) over night or chlorine dosing will kill the bacteria which then should be flushed out of the system or water heater. If the H2S gas smell returns – repeat or retain professional services.
The above can be verified at your state board of health (water well department) or a competent well drilling company.