Honest Woman

My Water has a Rotten Egg Odor, What is it and What do I do

That nasty smelling rotten egg odor is a result of bacteria producing hydrogen sulfide gas. Even minute amounts of H2S can be enough to ruin your otherwise perfect water and may be strong enough you can't even take a shower or be in the same room as running water.

Testing for H2S (Hydrogen Sulfide, rotten egg odor) must be done onsite. Even then accuracy is questionable at best.

The fact you smell the rotten egg odor is as good as any test to tell us it is present and treatment is necessary.

If you’ve got H2S it must be treated to protect downstream treatment. It will cause existing treatment to fail as it coats filter media preventing the media from working as designed. If you want to see the full advantage of other water treatment you will have to treat the H2S problem.

Steps to solve the rotten egg odor problem

(you may want to have a plumber do this for you)

Plumbing work:

  • Check your untreated water to see if the problem exists. If it doesn’t then the odor causing bacteria are finding food in your plumbing system. If it does the root of the problem is with your supply.
  • Check any filters you might have. Look for a cellulose based (usually pleated) filter and if found remove it from the system and replace with a non-cellulose filter. H2S bacteria are known to eat and thrive off of cellulose filter material.
  • Determine if the odor is on the hot water side only or if on both cold and hot.
    • If on hot side only you might be able to mitigate the problem by replacing your factory hot water tank anode with an aluminum / zinc anode.
  • After removing an cellulose based filters and swapping out your hot water heater anode the next step is to chlorinate your plumbing to kill the bacteria. This might need to be done several times as the goal is to kill the bacteria. These bacteria can hide in very small places inside your plumbing and if not killed the first time they will reproduce to the point of causing the odor to re-appear. Repeat chlorination is common.

Chlorinating to disinfect your plumbing

This is not a complicated process and the steps go like this:

  • Flush hot water tank till water runs clear.
    • Turn off your water and remove existing filters from your treatment system.
    • Clean your filter housings and add about a cup of bleach to the first housing and reinstall both housings.
  • Cold Water:
    • Go to the furthest water tap, turn it on and let it run until you smell chlorine.
    • Go to the next furthest water tap and repeat until chlorine odor is detected at every tap. If you need to add chlorine to the filter sump again to get the odor at a tap do so.
    • Let system sit with chlorine for several hours then flush.
      • Start with the furthest water tap and work your way back to the last tap flushing until you no longer smell chlorine.
  • Hot Water:
    • Repeat above process running hot water
    • After allowing chlorine to work for several hours flush all lines.
      • Start with the furthest water tap and work your way back to the last tap flushing until you no longer smell chlorine.

Repeat all above steps at first notice odor is re-appearing.

H2S Water Treatment:

  • Assuming the odor is not too terribly bad (you can still take a shower).
    • You will need to add an ICS-H to your treatment system to address the H2S problem and protect downstream treatment.
    • Repeat chlorinating process.
    • Replace existing downstream filters
  • Assuming the odor is terrible (you can’t take a shower or maybe not even able to be in the same room as running water). Or, the ICS-H just doesn’t quite take care of all the odor.
    • You will need to add an additional ICS-H or backwashing filter.
    • Repeat chlorinating process.
    • Replace existing downstream filters

Following these steps is a normal requirement when your water has a H2S rotten egg odor.

CAUTION: Please do not replace your existing filters before you’ve addressed the H2S problem as the H2S will cause premature failure.

Good To Know

Learn more about hydrogen sulfide treatment.

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