What is extraneous water in the sewer and why is extraneous water a problem for the sewer system, pumping stations and wastewater treatment?
Here you will find the 10 most frequently asked questions and their answers on the subject of extraneous water.
Do you have any further questions? Feel free to call us at 05361 28-1250 and we will be happy to answer your questions in a personal conversation.
Extraneous water is rainwater or groundwater that enters the sanitary sewer system but does not belong there. Causes of extraneous water are:
- leaking wastewater pipes through which groundwater enters the wastewater sewer system;
- unauthorized storm water discharged into the foul sewer (downspouts or yard drains incorrectly connected to foul water);
- Drainage water pipes connected to the wastewater sewer without permission.
Extraneous water, i.e. rainwater or groundwater, does not require wastewater treatment. Therefore, extraneous water unnecessarily burdens the sewer systems, pumping stations and wastewater treatment plants, leads to flooding in the wastewater sewer and causes considerable additional costs. In buildings with missing backwater protection, such a flood in the sewer can lead to backwater into the building and wet basements. Thus, extraneous water discharges into the wastewater sewer primarily endanger the immediate neighborhood. In the wastewater treatment plant, extraneous water makes wastewater treatment more difficult.
The Wolfsburger Entwässerungsbetriebe (WEB) have in recent years:
- delimited areas with large amounts of extraneous water;
- carried out more extensive investigations, such as flow measurements, camera investigations, investigations with signal fog in individual areas;
- controlled the development of extraneous water;
- public sewers investigated and damage repaired.
These measures will be continued. The next task is also to eliminate extraneous water discharged from private properties. The WEB has identified individual properties from which extraneous water enters the wastewater sewer. The property owners will be asked to repair their property drainage system.
Check your property to make sure all drains and drainage systems are properly connected. Wastewater systems also age! Check the condition of your property drainage system at regular intervals, e.g. with a camera. Record the course of the pipelines and manholes in a plan so that incorrect connections can be avoided in a later construction project.
In Wolfsburg, extraneous water is a problem especially during heavy rain. During the heavy rain in May 2013, the volume of wastewater increased by a factor of 3.
Unfortunately, almost all districts in Wolfsburg are affected by extraneous water discharges. The WEB is investigating the entire city area step by step in order to identify sources of extraneous water and to reduce the inflow of extraneous water. The help of the property owners is important for this. With a length that corresponds to about 3 times the length of the public sewage system, private sewage systems represent a significant source of extraneous water.
Incorrect connections can be detected by examination with:
- Signal Fog
- Sewer camera
- on-site inspections
can be detected.
A simple test to determine for yourself if something is incorrectly connected is to pour water down a drain and look in the transfer manhole to see where it arrives. If the water from the stormwater downspouts arrives in the stormwater transfer manhole, they are properly connected. Water from toilets, sinks, washing machines and showers must arrive in the wastewater transfer manhole. Some properties have drainage installed in the ground around the building. The drainage water may only be discharged into the storm sewer or combined sewer.
If you are found to have a wrong connection, you will be informed of this result by the WEB staff. You will be given a reasonable period of time to rectify the incorrect connection. The colleagues of the WEB will be happy to provide you with advice. If you are missing drainage plans of your property, you can obtain a copy of existing drainage plans of your property from us. This service is free of charge for you.
Contact the WEB. The colleagues of the WEB are at your disposal for a consultation. If you are missing drainage plans of your property, you can obtain a copy of existing drainage plans of your property from us. This service is free of charge for you.
Please note that any alteration of underground private sewage pipes is generally subject to approval.
Application forms to apply for a drainage permit (also required for structural alterations):
Note: The following documents are available here in *PDF format and will each open in a new window.