Strong sulpher smell and discolored water

I inspected a home that had been vacant possibly a year. When I turned on the water a strong sulpher smell filled the home and the water was very discolored from each fixture. The home is near a large lake so I don’t know if the lake has “turned” and a higher bacteria content has been noticed at the treatment plant. The hot water heater was off due to a gas leak at the regulator, so I am not sure the anode rod is the cause. High levels of H2S can be damaging to the water supply lines so I recommended the water quality be tested. I assume that since the home has been vacant for some time a build up of bacteria is now present in the lines. Any ideas out there?

The water heater may need to have a chlorine flush done to see if the smell and discoloration goes away. The water heater could have sediment in the bottom. Typically the drain valve does not empty the water heater completely. Recommend evaluation and correction by a licensed plumber. if the sediment build up in the tank is bad enough the tank may need replaced.


What does the water look and smell like at the service entrance/ hose bib ?

The color is from the sediment at the bottom of the tank and its just sitting there for some time. The smell is the disintegration of the sacrificial anode tube. We get that smell here all the time because of all the snow birds and the houses sit vacant. Many times just put a hose on the drain at the bottom of the water heater and then open it…it will flush out. Replace the sacrificial anode tubes if needed and all should be ok…at least most of the time. I usually let it run for about 30 minutes.

That is Hydrogen Sulfide produced by sulfur reducing bacteria growing in the tank. Usually occurs and is most noticeable in houses that have been uninhabited for a while. When I encounter this, I will leave hot water tap running full bore in the tub. You will get the characteristic black / purple cloudy staining most intensely just as the hot water in the tank is about to run out.

Sometimes it can just be flushed out, sometimes you will need to change out the magnesium sacrificial anode to another type (aluminum). In extreme cases it can be treated by overheating the tank (hazardous) or chlorine shock treatment. Both should be left to the plumber.

They say that in extreme cases a hydrogen bubble can form in the top of the tank which can ignite if the faucet is opened near an open source of flame (that would be exiting). :shock:

This is wordy, but covers all the possible reasons and solutions. It’s what I use and you’re welcome to it.


The potable water produced a sulphur-like odor. The odor results from the presence of hydrogen sulfide (H2S) gas. Sources of the gas include chemical reactions with sulphur containing minerals in the soil or rock and bacteria which convert sulphur compounds to H2S gas. Water heaters can produce H2S gas by providing a warm environment for the bacteria to live and the anode, which contains magnesium, supplies electrons that sustain the reaction of sulfate to H2S gas.

In an attempt to diagnose the problem, we suggest that you try to determine the source of the odor. 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.

  • 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 ground water.

If the source is your water heater:

  • Remove or replace the magnesium anode.
  • Disinfect and flush the water heater with a bleach solution.
  • Increase the water temperature to 160 degrees Fahrenheit for several hours to kill the bacteria, then flush the heater.
  • If you are not very familiar with water heater operation and maintenance, contact a plumber or water heater dealer to perform the service.

If the source is sulfur-reducing bacteria in the well or plumbing, the well will need to be disinfected. You should consult a well water specialist.

If the source is sulfur-reducing bacteria in a water softener or treatment unit, contact the manufacturer for instructions on disinfecting the unit. If the source is hydrogen sulfide gas in the ground water the water may be treated by use of activated carbon filters, manganese green sand filters, or oxidation filtration systems and you should consult a water quality specialist.

All the above is general information and you should consult a plumber or water quality specialist for specific guidance.

Thanks for the insight. The water at the hose bib was clear. As mentioned the house has been vacant for some time so I may have been the first to run some water through in some time. I did mention to the buyer in the report about the anode rod.

The hot water heater was off at the time of inspection and the odor was coming from the cold side. I did turn on the hot water heater and the smell was present on the hot side as well. The water was clear and I noticed no odor at the exterior faucet.


If you’re in the eastern area of Slidell, Louisiana, that’s just the nature of the water there.

Brackish water in the water heater. Drain/flush out the tank and refill.

Was this city water or well water? When I bought my home the well water was a yellow color and the smell was very strong. After installing a water filtration system with a 129 gal holding tank which was chlorinated and then filtered the water through both charcoal and resin filters the water is soft and we can drink right from the faucet.