Fountains in the home garden are a stylish decorative element and ideally they provide water for free. No wonder, then, that they are becoming increasingly popular. But whether newly built or years old, it can happen that the well water stinks. This can have different causes. Usually the smell gives an indication of where the problem is. Find out more in the professional magazine.

Odor – Chlorine scent


If a chlorine smell is noticed in the well water, this does not necessarily require a countermeasure. Chlorine is mainly used by the waterworks after heavy rain showers, as this causes the soil to lose its filtering functions. The chlorine is used to help with this task and to kill bacteria in the ground water. A maximum value of 0.3 milligrams per liter is normal. Sensitive noses can certainly smell this. The body can tolerate chlorine in this small amount, but it is still advisable not to use the well water as drinking water until a day or two after heavy rain showers. By then, the odor and, accordingly, the chlorine content should have subsided.

well cleaning

Over time, all sorts of substances settle in the well, especially if it has a continuously high water level and only little well water is drawn. Many well owners clean/sanitize their free water source with chlorinated cleaners. The chlorine is distributed in the water and can sometimes remain on the well walls. It requires a thorough flushing of the well and/or a full drawdown of the well water to remove all traces of the chlorine-based cleaning agent. If you have a lot of patience, you can wait until the chlorine has gone. The higher the well walls and water level, the longer it takes.

Tip: Instead of cleaning with agents containing chlorine, so-called UV processes can be used. These destroy bacteria just as reliably as chlorine.

Oil smell with or without an oil film

New fountains

An oil smell is often noticeable after a new well has been put into operation. Although forbidden, some well builders use a so-called cutting oil for construction machines/well drills because it protects against corrosion, among other things. However, it is insoluble in water and often settles on the walls. When it comes into contact with water, a light oil film usually forms and above all there is an oil smell. The well builder should be informed immediately and asked to remedy the problem.

Polluted groundwater

There is not always an oil smell and oil film on the well digger. It is quite possible that oil from the immediate vicinity has gotten into the groundwater. This can result from an oil change in the neighbor’s car or from an engine that has oil spilling onto an unpaved surface. Other causes of oil in groundwater are also possible. The problem can usually be solved by emptying the well until the odor and oil film have disappeared.

Note: If the smell of oil cannot be easily removed and it is certain that there is no oil pollution on your own property, the environmental agency should be contacted to get to the bottom of the cause and to solve the problem.

musty smell

If well water stinks of mold, as is often the case in ponds, this is usually due to intensive biofilm formation in the well or in the pipe systems. This is a slime that increases in stench as the mass increases. It is made up of the following substances in well areas and pipelines:

  • bacteria
  • algae
  • mushrooms


The usually viscous mucus is often difficult to remove. Various products are available with which you can carry out pipe cleaning yourself. The best and most reliable way is to hire a specialist company that will clean your pipes and wells for you. When digging a well, care should be taken to ensure that only smooth-coated materials are used, because the slime mainly settles on rough surfaces.


If the well water smells of faeces, it is definitely a case of infiltration of foreign water from drain pipes. Basically, only the well digger or a plumbing specialist can tell why and wherefore. The cause must be investigated and the damage repaired. Then pump out the well water until it no longer stinks of faeces.

Possible causes are often:

  • Damaged sewage pipe due to well construction – faeces run directly into the groundwater
  • Broken sewer pipe
  • Leaking septic tank set in the ground or leaking holding tank (can also be with neighbors)
  • Rotten (egg) odor

If the well water generally stinks of foulness or if the smell of the water is reminiscent of rotten eggs, the causes here are usually organic or inorganic substances that are in the earth. A foul smell can also come from compost meant to rot in the soil, as well as artificial fertilizer. Watering or rain causes the substances to penetrate deeper into the soil. When hydrogen sulfide forms, there is a foul odor that spreads into the groundwater system. When the groundwater reaches the well area, the stench rises up and naturally into the well water.

Fix and Handling

  • Wait until rotting is complete and hydrogen sulfide formation decreases
  • Search the surrounding soil for said substances and, if necessary, replace the soil in the immediate vicinity
  • Filter out the hydrogen sulphide from the water in the well using a special filter system
  • A well ventilation supports the rapid withdrawal of the gas
  • H2S is highly toxic in high doses and must not enter the body under any circumstances
  • iron and manganese

Rusty pipelines in the area or other iron and manganese in the soil can give the water in the well area a typical metallic odor. This can also be tasted. As the odor increases, the water turns reddish-brown. It stains fabrics and other metals.


If a rusty pipe in the ground is to blame for the smell of metal in the water, you need to find it and replace it with a new one. Smaller metallic objects that are on the bottom of the floor can also be responsible. This should be searched accordingly and the water pumped for it. For clear, metal-free water, once the “culprit” has been removed, it is sufficient to pump out the water or to remove it from the garden fountain as far and as often as possible. With the subsequent flow of fresh, metal-free groundwater, the rust discoloration quickly disappears and there is no longer a smell of metal.

If well water stinks, this can have various causes. It becomes more expensive and/or time-consuming if the problem is underground. However, the foul smell of sulfur is the most common, which is easy to get under control with suitable filter technology and a little patience, as described here.

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