Rainwater; information on infiltration without a permit
Rainwater from paved areas should be returned to the natural water cycle as far as possible (= near-natural rainwater management).
Stand: 05.03.2024. Link zum BayernPortal
Informationen
Urban drainage used to mean draining rainwater as quickly and completely as possible in order to reduce the risk of flooding in the town. 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. Low-pollution rainwater (e.g. from roofs and courtyards, private and municipal roads) should therefore 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.
Subject to Section 8, a permit is not required for the discharge of collected precipitation water into the 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 1,000m2 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 system with type approval (see "Metal roofs" subpage).
Technical rules for the harmless discharge of collected precipitation water into the groundwater (TRENGW)
Notification of the Bavarian State Ministry of the Environment and Public Health
Technical regulations for the harmless discharge of collected rainwater into surface waters (TRENOG)
Notification of the Bavarian State Ministry of the Environment and Public Health
Dealing with rainwater
Program BEN - Assessment of the exemption of stormwater discharges
Site drainage
Approval authority for the approval of land drainage systems in the city of Erlangen.
The land drainage department of the building inspectorate is responsible for the enforcement of the drainage regulations (EWS) for
- Drainage permits for new buildings and conversions
- Approval of temporary wastewater discharges / construction water retention
- Leak tests in the Erlangen-West water protection area
- Advice on the renovation of connecting sewers and underground pipes
- Advice on drainage issues / backwater problems
Anschrift
Öffnungszeiten
On-site appointments by appointment only.