I have the roten egg smell in the hot water only, it sounds like the anode rod but which one or both?

Question

Is the primary or secondary rod the culprit, or could it be both rods?

Answer 1

You have an anode in your water heater that has reached it's last leg. Look on top of the heater and you will see a pipe plug. Turn the water off and depressurize the system you don't need to drain it. Thke the plug out and cut whats left off or just put a plug or new anode in it's place. No big deal really. If hot and cold stank you would have a real problem. If that doesn't do it, cut or replace them both.

Answer 2

The smell is hydrogen sulfide and as the other answers said it might just be the anode rod that needs a simple replacement, however, it may be a bit more serious . . . (BTW both anode rods should be the same material..)

Hydrogen sulfide smell can be caused by bacteria from a well or water supply which reacts with the magnesium anode rod or rods and creates hydrogen sulfide. So, the magnesium anode rods may need to be replaced with aluminum anode rods and the system thoroughly flushed. If the smell persists it may be necessary to have your water supply tested and appropriate action taken.

If after replacing the anode rods with aluminum and flushing the system the smell continues, the water heater will have to be drained and flushed with a mild chlorine solution which will kill the bacteria.

Now, if you have well water.. it may NOT be the water heater.. it may just be the water itself. H2S smell will not come out much with cold water -- but the heat will liberate more H2S smell such that you will notice it..

If that is the case, a whole house carbon "cartridge" type filter may help.. HD has a GE cartridge unit for $50 or so with 1" npt pipe fittings coupled with a carbon cartride that costs $30 (caution it needs to be replaced every 3-6 months)... This cartridge quick fix may will not work in extremely serious problems (which require major equipment to fix) but it helps if the smell is a minor.

Answer 3

Gunner has the answer here.