Water in the basement: a backup from the sewer
When water comes out of the floor gully, the shower or the toilet on the lower floor, the sewer is backing up. The waste water looks for the lowest open drain in the building, and that is the basement.
So the first point on this page is not about cleaning, it is about safety. After that comes how to read the situation and what matters on the phone.
What you can do right now
If water is already standing, safety comes before everything else. Sewage can be in contact with electricity and is a hygiene risk.
Do not go into the basement
Do not step into the water, not even briefly. Sockets, the fuse box, the heating and appliances may be under water. Keep children and pets away.
Switch off the power if you can do it safely
Switch off the circuit for that part of the building at the fuse box, if you can reach it dry and safely. If you cannot, leave it and call us.
Do not add any more water
Do not flush a toilet, do not start the washing machine or dishwasher, do not shower. Everything that goes in upstairs comes back out downstairs.
Do not pump while the sewer is still backed up
Water pumped into the same pipe comes straight back. Pumping out and drying only make sense once the cause has been dealt with.
Note where the water is coming out
Floor gully, shower, toilet or washing machine connection: that spot is the most useful clue for us. Also note since when it has been running and whether there was heavy rain beforehand.
Take photos before anything is cleared
If you can safely reach a spot from which the situation can be photographed, take pictures. That helps later when you report it to your insurer.
When to call us
- Water is coming out of a floor gully, shower or toilet on the lower floor.
- The water level keeps rising.
- There is a smell of sewage.
- After heavy rain, water comes back through the building drainage.
- Several flats or several buildings are affected.
- It has happened before and the cause was never established.
Where the water comes from
A backup from the sewer
If the pipe behind the building is blocked or the public sewer is overloaded, the water level in the pipe rises. The waste water comes out wherever the lowest open drain is, and that is almost always the basement.
Typical triggers are deposits and roots in the main house drain, a foreign object in the house connection, or very heavy rain in a short time.
A backflow protection that is there but not working
DIN 1986-100 provides that drainage points below the backwater level are protected against backflow, either by a lifting station or by a backflow valve. This paragraph describes the standard, not a promise about our work.
A backflow valve only closes if it moves freely and is clean. Dirty or blocked flaps only show up when it matters. So such a part needs checking regularly.
Not every basement flood comes from the sewer
Water can also press in through the wall from outside, run in through a light well, or come from a drinking water pipe. Those are different causes and different trades.
The difference usually shows at the point where it appears. If it comes out of a drain, it is waste water. If it runs down a wall or stands under the basement stairs, we are talking about something else. Tell us on the phone what you can see.
Common questions about water in the basement
How do I know it is a backup?
Because the water comes out of a drain rather than running down a wall. Usually there is a smell of sewage too, and it starts while a lot of water is draining in the building or in the area.
What is the backwater level?
The height to which waste water can rise in the sewer. As a rule the backwater level is the top of the road surface in front of the property. Everything below that is at risk without protection.
We have a backflow valve. Why is water still coming in?
A valve only closes if it moves freely and is clean. If residue is stuck in it or the seal has failed, it no longer closes. It also only protects the pipe it sits in.
Can I pump the basement out myself?
Only once the power and the access are safe and the cause has been dealt with. Before that the pumped water runs back through the same pipe. And nobody should stand in contaminated waste water without protective equipment.
Will the insurance pay?
That depends on your policy. Backflow is often a separate item in building and contents insurance and not included automatically. We are not allowed to give legal or insurance advice. Ask your insurer and document the situation.