What is causing noise

Low noise

When will it finally stop?!

What is loud doesn't have to be noise. But noise doesn't have to be loud either. Noise is disruptive sound - and it doesn't have to be deafening to be nerve-wracking.

Quiet background noises: Those affected report, among other things, sleep disorders, headaches and dizziness (source: flickr.com, Evil Erin).

Again and again, noise protection agencies receive reports from people who feel disturbed by quiet, often low-frequency noises. In many cases, these noises are close to the perception threshold, sometimes they are inaudible to third parties. Nevertheless, they can be a heavy burden for those affected. However, the search for the cause is often difficult. Finding the cause and solution is made more difficult by the fact that the noises can not only be of technical but also medical origin.


In an increasingly technological world, the human hearing is exposed to multiple stresses. In the living environment in particular, people are surrounded by more and more machines, devices and systems that can cause annoying noises. Such a noise does not necessarily have to be loud to be perceived as annoying. A deep, monotonous roar of a heating system, for example, can be a great burden for an affected person. The sleep phase is particularly critical.
However, a noise in the environment is not always the cause. More or less loud noises can also be simulated by our nervous system. For those affected, these are often hardly distinguishable from environmental noises. Often people are looking for an external sound source that doesn't even exist. The collective term for the different manifestations of subjective acoustic perceptions is called tinnitus.

External (technical) sources

Various simple observations can be used to find out whether an external sound source is actually present in a specific case. Ambient noise is much quieter if you close your ears. In addition, noises of technical origin usually only occur in a certain area, for example in a house or in an apartment. They can also be perceived by more than one person. However, it must be noted that not all people hear and feel equally well.

The following technical sources can be the cause of low noise interference (list is not exhaustive):

In the flat:

  • fridge
  • Ventilation noise

In the house:

  • Heating (circulation pump, burner, chimney noise)
  • Hot water circulation
  • Electric panel: electric meter, circuit breaker
  • Woofer (subwoofer)
  • Home cinema with vibrators (surround)

In the neighborhood:

  • Heating, ventilation and air conditioning systems
  • Industrial engines
  • Drinking water pipes
  • Hay blower
  • Heavy traffic or buses
  • railroad
  • Transformer station
Internal sources (tinnitus)

If a sound does not get quieter when you close your ears, and it can also be heard in different quiet places and by no other person, then it is probably tinnitus.
Tinnitus is an acoustic perception without an external sound source. Such noises in the ear can occur in many different acoustic forms, for example as ringing, whirring, grinding or humming. An estimated 15% of the European population is affected by tinnitus.
The causes are varied and mostly unknown. In addition to constant or sudden exposure to noise, sudden hearing loss or viral diseases, stress can also trigger tinnitus, for example. While acute tinnitus can resolve itself again, a permanent cure for chronic tinnitus is not yet possible. The application of stem cell therapies is still in its infancy.

Legal basis

Approaches to the applicable pollution control for external sources can be found in the Civil Code (Art. 679 + 684 ZGB) and in the Environmental Protection Act (USG). Since these are special noises which generally do not exceed any legal limit values, an individual assessment is necessary in each case. Here, the special situation can definitely be taken into account that, on the basis of the Environmental Protection Act, even quiet noises can be assessed as annoying.
In any case, the precautionary principle of the USG must be observed, according to which emissions must be limited to the extent that this is technically and operationally possible and economically viable.
The DIN standard 45680 provides valuable information for assessing low-frequency, low-level noises.


If a technical facility could be identified as the cause, the technical malfunction can be remedied in simple cases with a small change to the machine, device or line. It may be enough to change the operating mode, replace a defective device or loosen a rigid connection that transmits the sound. In difficult cases, however, it may also be necessary to renovate an entire system because it is outdated or installed in an unfavorable manner, for example.
If the disturbance cannot be eliminated or not defined, distraction or masking by an additional noise with a high level of acceptance, for example the splashing of a fountain or the sound of a sea surf over loudspeakers, can help.


Depending on the technical source, this category is either everyday noise without limit values ​​or noise with limit values. In practice, however, it is very unlikely that the legal limit values ​​will be exceeded due to the noise characteristics. This category is therefore treated as everyday noise and is therefore the responsibility of the local government concerned, in larger communities and cities usually their building authorities (noise from buildings and systems) or security authorities and the police (noise from human activities).

List of municipalities in Switzerland
(Wikipedia; link to the municipal administration in the service column [right] on the municipality's details page)

Most municipalities keep the rules of the game on noise within the framework of a municipality or police ordinance.

Example police ordinance (extract from noise protection)


Federal and administrative court decisions on quiet background noises

A collection of federal and administrative court decisions on various types of noise can be found in the “Noise links” section. The list is continuously updated. There are currently no court rulings on this subject in the collection.


Enforcement aids

Cercle Bruit

The Association of Cantonal Noise Protection Experts (Cercle Bruit) provides enforcement aids and other documents on noise-specific topics. The documents come from the federal government, cantons, specialist agencies and associations.

Enforcement folder: 9.12 Low-frequency noises


foreign countries
Associations and Organizations