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My Well Water Smells Like Rotten Eggs

A rotten egg odor in your well water is often from Hydrogen Sulfide (H2S) gas.  The information provided below may help you both diagnose and treat this issue. 

Typical Sources:

  1. Your source water may contain sulfur from the natural decay of organic material or the breakdown of sulfur-containing minerals and rock.
  2. Bacteria which reduce naturally occuring sulfur compounds to Hydrogen Sulfide gas as part of their metabolism.
  3. Chemical transformation of Sulfur containing materials to Hydrogen Sulfide gas.


  1. Hydrogen sulfide is not generally an immediate health concern for people living in the home or consuming the water.  It is a taste and smell issue for consumption.
  2. Sulfur Reducing bacteria living within the water lines can produce a slime that serves to promote the growth of other bacteria.
  3. Production of Hydrogen Sulfide gas in the home can corrode copper piping and fixtures as well as tarnish silverware.

Track down the Source:

The easiest way to track down the source is by doing the "sniff" test from samples taken throughout the house.  It helps with the sniff test if the water has be off for several hours, and you have been outside the house for some time. 

  1. Your water heater:  your hot water smells, your cold water does not.
  2. Your water softener: Both hot and cold treated water smells, untreated water does not.
  3. Your piping:  Both hot and cold water smell initially, but stop smelling if the water is allowed to run for a while.
  4. Your well:  Both hot and cold water smell, and continue to smell even after allowing to run for a while.


Water Heater: 

If the source is the water heater, it could be caused either by the sacrificial anode, or by bacteria within the water heater. 

  1. Replace the magnesium anode with an aluminum anode (check to make sure this works with your heater and does not void any warranty). 
  2. Increase the temparature of the water heater to >160 degrees for several hours to kill bacteria, reset to the origianal setting. Flush the system completely to prevent scalding injuries. 
  3. Disinfect and flush the waterheater with a chlorine solution.

Water Softener: 

Disinfect according to manufacturers instructions. 

Piping or Well water

  1. Disinfect the well.  Call ES&C today to schedule to have your well disinfected.
  2. If disinfections does not work, then sulfide reduction can be achieved through the use of water treatment systems including: activated carbon, greensand filters, or oxidation systems.