Sulfur and Rotten-Egg Smelling Water in Northwest Arkansas
A rotten-egg smell is hydrogen sulfide gas. It is one of the most unpleasant water problems there is, and also one of the most satisfying to solve, because the fix is usually decisive once you have identified the source correctly.
That last part is the whole job. There are three quite different reasons water smells of sulfur, and they call for three different responses — one of which costs almost nothing.
Common symptoms
People describe this problem to us in these ways. You may recognise several, or only one.
- A rotten-egg or sewer smell when a tap is first opened
- The smell noticeable only in hot water
- The smell noticeable at every tap, hot and cold
- Smell that fades after running the tap for a minute
- Tarnishing on silver and darkening of copper or brass fixtures
- Guests noticing it when you have stopped being able to
Potential causes
Sulfur bacteria or hydrogen sulfide in the well or aquifer
Naturally occurring in some Ozark groundwater, particularly in deeper wells. This produces a smell at every tap, hot and cold.
A reaction inside the water heater
The magnesium sacrificial anode rod fitted to most water heaters can react with sulfate-reducing bacteria in the tank to produce hydrogen sulfide. This is the classic hot-water-only smell, and the answer is usually a water-heater service and a different anode rod, not a filtration system.
Bacterial growth in the well, plumbing, or a fixture
Sometimes localised to a single seldom-used tap or a drain rather than the water at all — a smelly drain trap can convincingly imitate smelly water.
Decaying organic matter reaching a shallow or poorly sealed well
Worth ruling out because it can indicate a well-construction problem that needs fixing regardless of odour.
Partly visible, but testing gives the answer
Start with a test you can do yourself in two minutes, because it narrows the possibilities enormously:
- Run the cold tap at the kitchen sink for a minute and smell it.
- Run the hot tap and smell that.
- Fill a glass, take it to another room, and smell it there.
Hot only points at the water heater. Both hot and cold points at the source. A smell that vanishes once the glass leaves the room was the drain, not the water. Confirming the source and its concentration, and checking for the iron and manganese that often accompany it, is what a water test is for.
Treatment technologies commonly used
Which of these is right depends on what your water actually measures. These are the technologies genuinely used for this problem, not a list of everything we sell.
Sulfur & Rotten-Egg Odor Treatment
The dedicated page covering aeration, oxidising filtration and chlorination approaches, and when each is appropriate.
Iron & Manganese Filtration
Sulfur very often travels with iron and manganese in Ozark groundwater, and a single oxidising filter may address more than one problem.
Well-Water Filtration
The whole-system view for a private well.
Carbon Filtration Systems
Suitable for low concentrations, but carbon alone is quickly overwhelmed by a persistent sulfide source.
Questions we are asked about this
The smell is only in my hot water. Do I need a filtration system?
Probably not. Hot-water-only sulfur smell usually comes from a reaction involving the anode rod inside the water heater. That is a water-heater service item. We will tell you this rather than sell you a filter, because a filter would not fix it.
Is hydrogen sulfide in water dangerous?
At the concentrations typically found in household water the main problem is that it is offensive, and that it corrodes metal fixtures and tarnishes silver. It becomes a genuine safety concern at much higher concentrations than a household tap normally produces. Testing establishes where you actually are.
Will a water softener remove the smell?
A softener is designed to remove hardness minerals, not dissolved gas. Some customers report an incidental improvement, but a softener is the wrong tool for this job and buying one for odour usually ends in disappointment.
Can the smell come back after treatment?
It can, particularly where bacteria are involved and where a system is not maintained on schedule. Media that works by oxidation needs periodic regeneration or replacement, and a well that has been shock-chlorinated can be recolonised. This is a problem that rewards a maintenance plan.
We work across Northwest Arkansas
City water and private wells, in Benton, Washington, Madison and Carroll counties.