Rotten Egg Smell?

Does your water smell or taste like rotten eggs?

You are actually smelling Hydrogen Sulphide Gas (H2S).

Apart from that special smell/taste, it is very corrosive to piping and turns water black.

It doesn't require a high concentration to be noticed - the level can be as low as 0.05mg/L.

Where does the H2S come from?

Well Water

  • Occurs naturally in the water

  • Due to presence of sulphate-reducing bacteria in the well.

    Ponds or Dugouts

    Probably it will be most noticeable in Winter and Spring.

    It is a by-product of decomposing vegetation, weeds and algae and is caused by the lack of dissolved oxygen in the water.


    To solve: Combine aeration of pond with a good, consistent maintenance program.

    Water Heaters

    If you only smell the odor when hot water is running, there may be a biochemical reaction occurring in the hot water heater between:

  • sulphates in the water;

  • sulphate-reducing bacteria

  • a magnesium rod in the hot water or

  • organic matter in the water.

    To solve:

  • To reduce sulphate-reducing bacteria: disinfect the water heater with chlorine bleach or hydrogen peroxide.

  • Where the reaction with the magnesium rod causes the odor problem, replace with a zinc rod. These rods are placed in the water to reduce premature corrosion of the tank. (aka: 'sacrificial' rods)

    Water treatment system options:

    Chlorination and sand filter

    Install a chlorine feeder and a sand filter.

  • H2S is oxidized by the chlorine.

  • The sand or crushed anthracite filter traps any insoluble sulphide particles.

    It requires about 2 mg/L chlorine to remove 1 mg/L H2S.

    Bonus: This system will also remove iron if present.

    One last step before you drink the water .........Purify It

    Simply install a point-of-use water purifier featuring:

  • Carbon block filter to remove chlorine taste and odor

  • Multi-web filter down to 2 Microns to trap particles and bad-stuff like cysts, Ecoli etc....

  • UV light to neutralize harmful bacteria molecules.

    There are models available that are about the size of a blender that can sit on the counter, or be placed under the counter. Typically, 5,000 L can be processed before requiring a replacement filter or annually.

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