Sulphur smell

[Bill Smith]

The house has been unoccupied for 5 or 6 months. When the hot water was run, there was a STRONG sulphur smell. There was no smell from the cold side. Could this be the result of water sitting in the tank for a long period of time?

[Michael Larson]

Originally Posted by bsmith

The house has been unoccupied for 5 or 6 months. When the hot water was run, there was a STRONG sulphur smell. There was no smell from the cold side. Could this be the result of water sitting in the tank for a long period of time?

How is hydrogen sulfide gas produced in a water heater?
A water heater can provide an ideal environment for the conversion of sulfate to hydrogen sulfide gas. The water heater can produce hydrogen sulfide gas in two ways - creating a warm environment where sulfur bacteria can live, and sustaining a reaction between sulfate in the water and the water heater anode. A water heater usually contains a metal rod called an "anode," which is installed to reduce corrosion of the water heater tank. The anode is usually made of magnesium metal, which can supply electrons that aid in the conversion of sulfate to hydrogen sulfide gas. The anode is 1/2 to 3/4 inches in diameter and 30 to 40 inches long.

What can I do about a problem water heater?
Unless you are very familiar with the operation and maintenance of the water heater, you should contact a water system professional, such as a plumber, to do the work.

• Replace or remove the magnesium anode. Many water heaters have a magnesium anode, which is attached to a plug located on top of the water heater. It can be removed by turning off the water, releasing the pressure from the water heater, and unscrewing the plug. Be sure to plug the hole. Removal of the anode, however, may significantly decrease the life of the water heater. You may wish to consult with a reputable water heater dealer to determine if a replacement anode made of a different material, such as aluminum, can be installed. A replacement anode may provide corrosion protection without contributing to the production of hydrogen sulfide gas.
• Disinfect and flush the water heater with a chlorine bleach solution. Chlorination can kill sulfur bacteria, if done properly. If all bacteria are not destroyed by chlorination, the problem may return within a few weeks.
• Increase the water heater temperature to 160 degrees Fahrenheit (71 degrees Celsius) for several hours. This will destroy the sulfur bacteria. Flushing to remove the dead bacteria after treatment should control the odor problem.

CAUTION: Increasing the water heater temperature can be dangerous. Before proceeding, consult with the manufacturer or dealer regarding an operable pressure relief valve, and for other recommendations. Be sure to lower the thermostat setting and make certain the water temperature is reduced following treatment to prevent injury from scalding hot water and to avoid high energy costs.

[Bill Smith]

You are the best Michael - Thanks!