The sewer pipe in the kitchen often goes backwards and is not blocked at ordinary times. What is the reason? The water overflowed as soon as it was big. What's the solution?

Causes and solutions of water returning from kitchen sewer;

There is a jam.

It is most likely that there is a blockage under the sewage main. Once the sewage is not discharged smoothly, the sewage will flow back to the nearest outlet from the blockage point. You can't handle this situation, you can only dredge the pipeline company.

Main pipe blockage

If your home is on the second floor and the sewer water flows back to your home, it can be said that the pipeline below the second floor is blocked. This blockage is mainly caused by the blockage of the main sewer, that is, the main sewer from the first floor to the seventh floor is blocked, and the blockage position is generally at the 90-degree elbow from the manhole cover to the bottom of the first floor, so the sewer flows back to the second floor.

Poor hydraulic conditions

Residential drainage is generally gravity drainage, sewage is discharged into drainage riser first, and then discharged into horizontal drainage main pipe by residential sanitary ware. And finally discharged into an outdoor drainage inspection well. In general, the drainage speed of drainage riser is higher than that of horizontal drainage main pipe. When the sewage is discharged to the bottom of the drainage riser and transferred to the horizontal drainage main pipe, instantaneous blockage will occur, and a short section of positive pressure water column will be formed at the bottom of the drainage riser. If the hydraulic conditions there are not good (for example, there are no two 45 elbows when the drainage riser is connected to the horizontal drainage main pipe, and the horizontal drainage main pipe has a small diameter, a small slope, or is blocked), the positive pressure water column will be higher. When the positive pressure water column is higher than the sanitation of the first floor residence,

Pipeline problem

In the past, the drainage pipes of residential buildings were generally sand cast iron pipes, with rough inner walls, easy to hang dirty, poor anti-corrosion and easy to rust, which led to poor drainage. However, the inner walls of plastic drainage pipes and machine-made centrifugal cast iron pipes are smooth, so they are not easily blocked by dirt, and their water passing capacity is greater than that of sand drainage cast iron pipes 10%~26%. Local construction committees have banned the use of sand drainage cast iron pipes in new residential projects, and promoted the use of plastic drainage pipes and centrifugal cast iron pipes.

Large residential area

In residential construction, the slope of the horizontal main drainage pipe generally meets the standard slope, and the velocity of sewage in the pipe can reach the self-purification velocity. When the house was first built, it was normal because of its own weight and false foundation settlement. However, in the design and construction, it did not attract great attention and did not take corresponding measures, which led to the large settlement of the house and the crushing of the drainage outlet pipe, thus causing the slope of the drainage outlet pipe to decrease or even reverse. In severe cases, it will crush the drainage outlet pipe, resulting in poor drainage.