Precipitation water; application for a permit or permit amendment for direct discharge into water bodies

If you want to infiltrate rainwater or discharge it into a surface water body, you generally require a permit under water law.

If you wish to change a project for which you have a permit under water law, you must apply to the relevant district administrative authority for a change of permit.

Precipitation water is water that runs off from built-up or paved areas.

Surface waters are rivers, lakes, canals, streams, ditches and ponds.

Permission is not required for discharges into groundwater if no adverse changes to the groundwater are to be expected. The discharge is harmless if the "Ordinance on the Permission-free Harmless Infiltration of Collected Precipitation Water" (Precipitation Water Exemption Ordinance - NWFreiV) and the "Technical Rules for the Harmless Discharge of Collected Precipitation Water into Groundwater" (TRENGW) are complied with. This is generally the case if the precipitation water drains from low-polluted areas and is not discharged into protected areas. The permit requirement for discharging into surface waters does not apply if the "Technical Rules for the Harmless Discharge of Collected Rainwater into Surface Waters" (TRENOG) are complied with.

If necessary, you can use the online procedure to clarify whether you need to apply for a permit. There are online procedures that determine at the end of the form entry whether the discharge does not require a permit or whether you need to apply for a permit under water law. You can then submit the application digitally to your district administrative authority.

The permit specifies the type and extent of use. It may be subject to conditions and ancillary provisions. In contrast to an authorization, a permit can be revoked by the district administrative authorities.

Precipitation water that runs off from built-up or paved areas is wastewater within the meaning of the Water Resources Act (Section 54 (1) No. 2 WHG).

The targeted discharge of collected precipitation water into a body of water (surface water or groundwater) generally constitutes a use of water that requires a permit under water law in accordance with Section 8 (1) WHG. A permit for the discharge of precipitation water may only be granted if the quantity and harmfulness of the wastewater is kept as low as possible in compliance with the relevant procedures according to the state of the art (§ 57 Para. 1 No. 1 WHG).

In each individual case, it must be examined whether and how the harmfulness of the precipitation water discharge can be kept as low as possible.

For this purpose, the generally recognized rules of technology of the relevant leaflets and worksheets of the German Association for Water, Wastewater and Waste (DWA) must be taken into account. The application is specified in the relevant information sheets of the Bavarian State Office for the Environment (LfU). The necessary requirements are determined by the responsible water management office, which examines the submitted application documents as an official expert in the water rights procedure.

If the examination shows that the quantity and harmfulness of the precipitation water to be discharged - through any necessary measures, such as the creation of a retention volume or appropriate pre-treatment measures - meets the requirements for the specific discharge, the permit under water law can be issued.

Subject to Section 8 of the NWFreiV and TRENGW or TRENOG, a permit is not required for the discharge of collected precipitation water into a body of water (surface water or groundwater) (Section 9 (1) No. 4 WHG) if the essential requirements are met:

• The precipitation water is infiltrated over a suitable topsoil layer.
• Underground infiltration systems such as infiltration trenches, seepage pipes or shafts are only permitted if surface infiltration is not possible and appropriate pre-treatment is carried out.
• A maximum of 1,000 m2 of paved area may be connected to an infiltration system.
• Infiltration takes place outside of water and medicinal spring protection areas and outside of contaminated sites and suspected contaminated sites.
• The rainwater to be infiltrated is not adversely modified or mixed with wastewater or substances hazardous to water.
• The rainwater to be infiltrated does not originate from areas where substances hazardous to water are regularly handled (except for small containers up to 20 liters).
• Rainwater from uncoated copper, zinc or lead surfaces over 50m2 may only be infiltrated after pre-cleaning the water via a suitable topsoil layer or after pre-cleaning via a treatment plant with type approval.

You can apply for a permit for the direct discharge of precipitation water from the district administrative authority responsible for you. The general procedure is as follows:

• Send your application for a permit with the required documents to the responsible district administrative authority, preferably using the online procedure provided.
• The district administrative authority
  • checks that your application and documents are complete and will contact you if any information or documents are missing,
  • checks your application from a water management and water law perspective and involves other authorities if necessary.
• You will receive a permit or a rejection notice.
• You will also receive a fee notice.
• You pay the fee.

You can apply for an amendment to the permit for the direct discharge of precipitation water at the district administrative authority responsible for you. The general procedure is as follows:

• Send your application for a permit change with the required documents to the responsible district administrative authority.
• The district administrative authority
• • checks that your application and documents are complete and contacts you if any information or documents are missing,
  • examines your application from a water management and water law perspective and, if necessary, involves other authorities.
• You will receive an amendment notice for the permit or a rejection notice.
• You will also receive a fee notice.
• You pay the fee.

Urban drainage used to mean draining rainwater as quickly and completely as possible in order to reduce the risk of flooding in the area. Nowadays, the aim is to minimize the impact on the natural balance of the water cycle by using rainwater in a "near-natural" way. This brings not only water management but also financial benefits. Rapid drainage of water impairs groundwater recharge and shifts the risk of flooding onto downstream residents.

The principle of all construction activities should be to intervene as little as possible in the water balance, for example by using water-permeable surfaces or green roofs. However, if intervention cannot be avoided, it can at least be limited by near-natural, decentralized rainwater management. Therefore, slightly polluted rainwater (e.g. from roofs and courtyards, private and municipal roads) should be infiltrated on site, collected and used (e.g. for watering gardens or flushing toilets) or at least retained decentrally and discharged in doses into streams and rivers. No permit is usually required for the infiltration or discharge of rainwater if the relevant technical regulations are observed.

There is no statutory deadline. Apply for the permit in good time before starting your project.

The processing time when applying for a permit depends in particular on the quality and scope of your application and the documents.