If you want to discharge wastewater into a private wastewater system, you need a permit. Under certain conditions, the permit requirement does not apply. You apply for the permit from the responsible authority.

Public wastewater facilities are available to the general public, private facilities are available to a restricted group of users, for example companies in a chemical park.

For certain industries and activities (such as the chemical industry, paper production, metal processing, cooling water use), pollutants are to be expected in the wastewater that are not sufficiently purified in a municipal wastewater treatment plant. Requirements for this are set out in the sector-specific annexes to the Waste Water Ordinance.

In order to comply with these requirements, special measures and wastewater pre-treatment plants are required to reduce the pollutant load so that the wastewater can then be purified without harm in a public or private wastewater treatment plant.