ODOR - Stinky - Rotten Egg - ( Hydrogen Sulfide - H2S ) in Well Water
Most noticeable when water is first turned on ( because the gas separates from the water and collects in the pipes as the water sits ).
If you notice this smell in your water, it probably contains hydrogen sulfide (H2S) gas. Sources of this gas include:
- Decay of organic matter or chemical reactions with sulfur-containing minerals in soil and rock.
- Sulfate-reducing bacteria which convert naturally occurring sulfate and other sulfur compounds to hydrogen sulfide gas.
- Water
heaters can produce hydrogen sulfide gas by:
- Providing a warm environment for sulfate-reducing bacteria to live.
- The anode, which is usually magnesium, supplies electrons that sustain the reaction of sulfate to hydrogen sulfide gas.
Should hydrogen sulfide gas or sulfur-reducing bacteria concern me?
The hydrogen
sulfide gas levels found in well water is not harmful to your health ( but friends and relatives will let you know your house stinks when they walk in the door). There is also the problem of sulfur-reducing bacteria generating ( growing ) a slime that can promote the growth of other bacteria and clog
wells and plumbing as thick layers start breaking off from pipes and inside of any tanks.
How do I determine the source?
Run water separately from both the cold and hot taps, preferably when you have been away from the house for a few hours so your sense of smell is more keen.
- If the smell is only from the hot water tap,
the source is most likely your water heater.(
caused by the self sacrificing rod installed in your hot water heater.
Removal of this rod by your plumber could solve this problem.
Helpful videos,
https://youtu.be/ZUOfZf4z6r8
and longer - more detailed video,
https://youtu.be/l6U8fu0oidQ - If the smell is from both hot and cold taps, but only from water treated by a water softener, you may have sulfur-reducing bacteria in your water softener.
- If the smell is from both taps and diminishes after the water runs, you may have sulfur-reducing bacteria in your well or piping.
- If the smell is from both taps and is persistent, you may have hydrogen sulfide gas in your groundwater
How can I eliminate hydrogen sulfide gas?
If the source is hydrogen sulfide gas in the groundwater the water may be treated by:
- Activated Carbon filters for hydrogen sulfide concentrations less than 2 mg/L.
- Manganese greensand / Katalox filters for hydrogen sulfide concentrations up to 5 mg/L.
- Oxidation filtration systems ( Aerator ) for hydrogen sulfide concentrations of any level up to 5mg/L. ( high levels require adding chlorination and carbon filtration).
- Chlorine injection system with 120 gallon contact tank and 1 ( or 1.5 ) cu.ft. Carbon Tank with backwashing valve after ward, and the problem is less then 3 mg/l ( ppm ).
The proper size equipment, levels of chemicals, and frequency of cleaning all depend on the amount of H2S in the water and how much water you use on a daily basis.
So, the first thing you need to do, before purchasing or adjusting equipment for H2S removal is to get an accurate test of the level in the water.
This is best done on site after running the source water for about 5 minutes.
Professional water treatment dealers have the test kits to accurately measure the levels in your water source, and will often test for free ( of course they will want to sell you some equipment too ),
or kits can be purchased online $ 50 - $ 100 is the common price range for a professional kit ).
*** Low Cost for Low Level Test Kit ( 2 ppm or less )
CUSTOMER WRITES:
I have increased the chlorine and it seems to be doing the trick. Thanks for all your help.
One last question, what did you mean by; Are you using extra water for irrigation lately? The irrigation water is drawn prior to the treatment system. How could that be a contributing factor?
** The more water used from the Well, the higher the concentration of hydrogen sulfide you will be "pulling up" from the ground. Some people have "no" odor, except when they use 50 - 100 gallons or more. And any Well that has hydrogen sulfide already, will have a higher concentration coming from the Well as the water demand increases ( i.e. watering the lawn, filling the swimming pool ) and as the actual water table in the ground drops ( during "dry spells" ).
Once the summer rains begin, and the water table rises back to normal levels, and less water is used, then the level of hydrogen sulfide in the water drops back to "normal" levels.
