Anode rod may be source of water odor
BY DWIGHT BARNETT Scripps Howard News Service

Q: Nine months ago I started to get a strong rotten-egg smell from the hot water. I cleaned out the water heater and flushed the pipes. This worked for a month. I found the anode rod loaded with a pastelike substance and the bottom of the electric water heater was rusted out. I replaced the water heater and flushed the pipes out again with bleach. Three months later the rottenegg smell was back.

I pulled the anode rod, and it was loaded with a pastelike substance and very corroded. I replaced the anode rod with one that was designed for a water system. Within 60 days the smell was back. The anode rod was loaded with the paste again. It seems I have to flush the system every 60 days to keep the rotten-egg smell out of the hot water.

Flushing the system every 60 days is getting old.

Is too much potassium being used in the system? I understand the hydrogensulfide problem, but wonder if the water system is helping to create the problem. The main water from the county has a lot of chlorine, so I would expect the problem would go away when the system is in bypass, which it does. Any help would be appreciated.

A: If the odor goes away when you switch to "bypass," then the problem is in your filtering system.

I'm no chemist, but as I understand it, the potassium chloride is used to remove minerals from the water supply, making the water "softer."

In most cases, it is the anode rod that creates the odors. However, anode rods made of magnesium and aluminum react quickly to softened water because the softened water increases the conductivity of the water.

From waterheaterrescue.com: "A sacrificial anode creates an electrical reaction inside a water heater as it corrodes, which can create the odors. A powered anode protects the tank's interior by feeding electricity into the tank.

"Since there is no magnesium or aluminum to corrode, there's no smell. I don't recommend them for everybody because they're several times more expensive than the common sacrificial anode. There are several configurations of residential water heaters. Most have a hex-shaped nut for the anode somewhere on the top of the tank. A few do not.

"Some of Bradford White's, A.O. Smith's and State's residential tanks employ a combo anode/hot-water outlet/nipple in the hot port. A powered anode can be used with those tanks by adding a brass tee to the hot port. The bottom port of the tee will connect to the tank while the plumbing for the house will go out the side of the 'tee,' the powered anode will screw into the top of the opening with the element hanging down inside the tank."