Water heater refuses to give up its sulfur smell
4 June 2005
A. The water technician may have not used the right word but he was heading in the right direction. The rule used to be if the water heater has an anode-- almost all do-- and the water stinks, pull it out. If itís magnesium -- and it most likely is-- ch ange it to zinc. Removing it completely will reduce the smell and may eliminate it but it will certainly void your warranty and may shorten the working life of the heater tank. Iíve known homeowners who have taken that route and struck the bargain of sho rter water heater tank life in favor of hot water that doesnít stink.
All wells in this area of which Iíve had any experience import some bacteria into the house. You can place a UVC sanitizer light on the well line and reduce that by 99.9% but most people donít do that and the bacteria generally isnít harmful to most huma ns. One of those strains of bugs that gets into the water heater is called sulfur-reducing bacteria (SRB) and lives in the tank giving off the very odor you describe. A water heater provides a good environment for SRBs because of the sacrificial anode. The anode helps protect the water heater by corroding instead of the tank lining like the zincs used in boating and to protect wire crab traps. SRBs are nourished by electrons released from the anode as it corrodes.
There are two ways of getting these bugs out. You can put a sanitizing agent into the water heater tank itself for a one-time cleansing or you can turn the thermostat of the water heater up to 140ļF. To do that you take the following steps. Step one i s to turn off the electrical power to the water heater. It will be a 30-amp 220v breaker in your electrical panel box and should be listed. If you cannot find the right breaker then donít go to steps two or three.
Step two is to remove the small covers on the side of the water heater tank to expose the rear of the heater elements. You may have to pull some insulation out to see them. Remember to put it back when you are done. Step three is to take a screwdriver and insert into the slotted screw at the rear of the element and turn it so the little arrow points to 140. Do it for both elements. Some water heaters only have one element so if you just have one donít worry, just set that one. Make sure both element s are set to the same temperature then replace the covers on the tank side and turn the power back on. It should take a few days but the elevated temperature should kill the bacteria and eliminate the smell. Some professionals recommend setting the elem ents even higher to 160ļ for awhile then back down to 140ļ. If you do that be sure you warn everyone in the house about it.
I donít know where the original setting of 140ļ came from but I do know that there are a whole bunch off nasty bugs that canít survive in water that hot, like SRB. Legionella pneumophila bacterium is another one. One way you get Legionnaireís disease is by taking a shower using water that has the bacteria in it and inhaling droplets of infected water. Itís happened. It wouldnít have if the setting was left at 140ļ. There are all sorts of plumbing devices that eliminate the potential of scalding and I recommend them.
Now, upping a water heaterís temperature to 140ļ and leaving it there is heresy to many for a number of commonly accepted reasons. The argument is that you donít need water hotter than 120ļ and to a great extent thatís true. It greatly reduces the scald ing hazard which is why the heaters were turned down to 120ļ from the 140ļ factory setting pre-1990 or so. It was the lawyers that drove that change, not water heater designers or enviromentalists. The lowered setting saves electricity because you are n ot storing water at a temperature that you are most likely to mix with cold water to use, rendering the whole idea of such hot water silly. It used to be that the manufacturers of dishwashers wanted 140ļ water but that need went away when they started in corporating a water heating feature into the washers themselves and the detergents got better.
Pulling the anode out of a water heater can be a lot more difficult than you might think depending upon the headroom you have above the tank. You turn off the water (and for me I turn the power off too, just to be sure), then open a hot water faucet to t ake the pressure off of the tank and unscrew the bolt of the anode and pull it up and out. Thatís easy if you have the room. Anodes donít like to bend. The worst case is you have to empty the tank of water, unhook all connections-- wire and pipe-- and place the tank on its side to pull the anode out. That can be a big job for a do-it-yourselver and if you think youíve got problems at home now, wait till you screw that job up and have to call a plumber to bail you out leaving the house without hot wa ter for hours if not days until the pros show up. I never attempt a plumbing repair on a weekend. Murphyís Law always awaits me.
Try the temperature tack first. Itís easier.