Precipitation/rainwater
The top priority should be to seal as few areas as possible and thus allow natural seepage.
Rainwater flows to a large extent via streams and lakes to the sea and seeps into the subsoil and is the part of the natural water cycle that contributes significantly to the recharge of groundwater.
As a result of increasing building development and the sealing of surfaces, rainwater only partially enters the water cycle naturally; it collects on roofs and paved surfaces such as courtyards, parking lots or roads and no longer seeps away.
This rainwater is often drained into the sewer system. Problems occur during heavy rainfall and snowmelt; the sewer system and rainwater retention basins can only absorb the water masses to a limited extent. Permission to discharge into the sewer system is granted by Wolfsburger Entwässerungsbetriebe (WEB).
For ecological and economic reasons, this form of drainage is no longer up to date, as rainwater in combined sewer systems, like wastewater, has to be treated at great expense in the sewage treatment plant or, in separate sewer systems, is fed directly into surface waters, which are subject to enormous fluctuations in volume.
A sensible alternative to this can be to use rainwater in the household or to infiltrate it. As wastewater charges are calculated separately for rainwater and wastewater, this can also reduce the costs for wastewater in individual cases.
Rainwater from a cistern can be used for watering the garden. A second water circuit in the house, e.g. for laundry and/or toilet flushing with rainwater, is permitted, but is not recommended by the public health department for hygienic reasons.
A second, calibrated water meter must be installed for the purpose of calculating wastewater charges.
Further information and the application form for registering a garden water meter can be found on our page on the property tax under "Wastewater charges".
Information on installing a garden water meter can also be found on the Wolfsburger Entwässerungsbetriebe (WEB) website.
In any case, a drinking water connection must be available, as a constant water supply via the cistern is not guaranteed, especially during periods of low rainfall. Complex filter technology is also required.
Another sensible form of rainwater drainage is infiltration on your own property.
Prerequisite:
- No significant adverse effects on the water balance and no impairment of the groundwater
- permeable subsoil (kf value)
- Sufficient absorption capacity of the subsoil (composition, thickness, groundwater table spacing)
- Ensure specifications for safe infiltration. Safe infiltration must be possible. Waterlogging or moisture damage to your own or neighboring houses can be very costly and time-consuming to rectify. It is therefore essential to consult a specialist before deciding on infiltration.
Taking the above criteria into account, there are different types of decentralized infiltration:
- Surface infiltration (rainwater essentially infiltrates on the surface on which the precipitation actually falls)
- Swale infiltration
- Infiltration trenches and pipe trench infiltration
The infiltration of rainwater from roofs (excluding uncoated roof coverings with copper, zinc and lead) and yard areas on the respective property via the living soil zone is not subject to approval.
However, rainwater infiltration is not always possible without prior cleaning, as the run-off from roads, parking lots and areas used by commercial enterprises, for example, can lead to contamination and pollution.
If infiltration is to take place via technical facilities (infiltration trenches or similar), a permit under water law must be applied for.
In water protection areas and the medicinal spring protection area of the Hoffmann spring in Fallersleben, rainwater may only be infiltrated with an official permit.