The principle of operation of sewer pipes is simple and largely based on the effects of gravitational laws. For this reason, most sewer conduits are laid with a certain inclination, providing a natural flow of sewage. Insufficient and paradoxically extreme bias promote the formation of jams in the pipes. If insufficient or no inclination drains quickly clogged by impurities. With strong bias water leaves no time will wash away grease particles, food waste residues and human waste products that are retained on the interior walls of the pipe.
When laying sewer should follow the rules specified in construction standards, which ratio ranges from 0.008 to 0.03 per meter. The value of 0.008 means that the edge of meter pipe must be raised to 8 mm, while the differential coefficient of 0.03 should be 3 centimeters. The table shows the recommended values for tilt common pipe diameters used for indoor and outdoor sewerage arrangement.
| Diameter | the optimal level of | The smallest allowable slope |
| 50 mm | 0.035 (35 mm) | 0.025 (25 mm) |
| 100 mm | 0.02 (20 mm) | 0.012 (12 mm) |
| 150 mm | 0.01 (10 mm) | 0.07 (7 mm) |
| 200 mm | 0.008 (8 mm) | 0.005 (5 mm) |
Calculate the slope of the pipeline can be of a simple formula for multiplying the desired length of bias-mounted pipes. For example, the overall length of the pipeline 10 meters with a diameter of 50 mm is multiplied by a coefficient of 0.035, the result is obtained that the difference between the pipe ends to be equal to 35 centimeters. To control the necessary inclination for mounting pipes used to level or protractor laser level. The use of measuring instruments allow relatively accurate adjustment of the required slope pipe.
Modern plastic pipes for sewer less susceptible to congestion, as have smooth inner walls. When installing sewer internal length of more than five meters must be installed with a tee plug, which will be cleaned congestion mechanically, using a special steel cable. As practice shows, the most common bottlenecks occur in small diameter pipes and installing a tee to clean will eliminate an emergency situation quickly.
