Drainage authorisationsAuthorisation to drain roof water for drainage can be granted by the municipality when the following conditions, cf. Executive Order no 501 of 21 June 1999 are fulfilled.
- Drainage must be carried out to a separate drainage system which no other forms of waste water are led to.
- The seepage system must be designed, placed and configured so that no other superficial run-off or inconvenience arises.
- The distance to the water catchment system, for which drinking water quality requirements have been laid down, must be at least 25 m.
- The distance to watercourses, lakes and the sea must be at least 25 m.
The distance to watercourses, lakes and the sea can be reduced if at the same time a discharge permit can be granted. A discharge permit is subject to the recipient quality being observed and the water catchment and groundwater resources not being contaminated.
In the environmental legislation, no rules have been laid down for the dimensioning and configuration of drywells.
All work with sewage systems within property boundaries must be carried out by authorised sewage contractors only.
The use of drywells with pipes for diverting rain water from roofs on residential buildings with attached houses, carports and garages or on operational buildings in agricultural properties is exempt from the requirement for authorisation as a sewage contractor.
This exemption is subject to the system being brought to the property’s own land and also being carried out in accordance with the regulations in the Danish Building Regulations and Environmental Protection Act.
The exemption does not permit the carrying out of plugging or other procedures in existing drainage installations without authorisation as a sewage contractor.
Seepage of rain water in drywells
Directions from Rørcentret (Danish Pipe centre) 009