Sewage slope for 1 meter: SNiP and standard system parameters

This article discusses in detail such a nuance of the installation of the system as the correct slope of the sewage system at 1 meter: SNiP and regulatory requirements that should be followed in practice, optimal indicators for certain sections, recommendations on the organization of the distribution of the pipeline. The text contains a review of common mistakes and tips to help avoid them, and formulas that should be relied upon during the design of the main line for drains.

Sewage slope for 1 meter: SNiP and standard system parameters

Sewage incline of 1 meter: SNiP and its role in the design of the system

Comfortable living in a country house is possible only if there is a system designed for the removal and disposal of household waste. For these purposes, used sewage autonomous type (centralized for apartments) or septic structure. Inside the system, the movement of waste fluid through the pipes is carried out in a pressure-free manner. In other words, polluted drains are transported to the site of purification by gravity. This is facilitated by natural gravity, which is achieved by the slope of the highway.

Sewage slope for 1 meter: SNiP and standard system parameters

Important! Natural gravity appears only if the sewer is located under a certain slope. In this case, the system will function normally only if the slope of the sewage system per meter of the pipeline complies with the regulatory requirements of the SNiP.

The optimum gradient also depends on additional factors:

  • diameter of pipeline elements;
  • the material from which the pipes are made;
  • schemes of external and internal placement of sewage.

Despite the seeming simplicity, as a result of the incorrect design of the sewage treatment facilities and the drainage line in the collectors, blockages and traffic jams can form, and the system itself will not be able to fully perform its main task.

How to avoid mistakes when installing sewage in the apartment with your own hands

When it comes to pipeline slope, it is important not to go to extremes. There are only two kinds of popular mistakes that inexperienced people make when building a sewage system.

Sewage slope for 1 meter: SNiP and standard system parameters

In the first case, the slope of the line is absent or it is not enough to move the fluid by gravity. As a result, the flow rate decreases, because of which dense fractions are not washed off, but remain on the inner walls of the pipes. There is a gradual accumulation of sediment, which develops into a blockage.

Partially waste water with impurities of fractions of different density lingers on the walls of the pipeline, as a result of which the pipeline is covered with sludge and begins to exude unpleasant odors that penetrate back into the room. Therefore, it is necessary to regularly clean the sewage system in a private house or apartment, where the installation of the system was performed in violation of the requirements.

Excessive tilting of the system can also create prerequisites for frequent cleaning for prevention. Intensive fluid flow at high speed will not be able to capture solid particles from the walls and wash them. Moreover, in the process of moving water, fecal fractions will be layered and pressed on the walls of the sewage system. In this case, all stop valves and pipe joints will be subjected to serious stress, which increases the risk of breakage. Therefore, it is very important to adhere to the recommended parameters attributed to the SNiP documents.

First of all, its diameter affects the throughput of a pipe. Therefore, it is recommended to select the angle of the pipeline laying on the basis of the cross-sectional dimensions of its elements. The larger the diameter of the product, the smaller will be the optimum slope for moving water.

The minimum allowable angles of inclination per 1 m of pipeline, taking into account its cross-section:

Pipe section, cm Minimum tilt angle
four 0.025
five 0.2
7.5 0.013
eleven 0.01
15 0.0007
20 0.0008


If the pipe diameter is 5 cm, then taking into account the minimum angle (0.02) after installing the system, the difference in height between the placement of the ends of the 1 m long section will be 2 cm.

Important! When distributing sewers in a private house, it is not recommended to install pipes at an inclination corresponding to the maximum allowable value.

Calculation of pipe fullness for use by SNiP 2.04.01-85 when installing internal sewage

Recommended parameters for the construction of domestic sewage clearly marked in the SNiP. These data are contained in the regulatory document 2.04.01-85, which can be used as a set of rules and the basis for the construction of a communication system for the withdrawal of stocks.

The calculation of the pipeline fullness indicator is carried out taking into account the characteristics of the material from which the elements of the system are made. On the basis of these data, it is possible to find out by means of calculations with what speed the drainage water must move along the sewage system so that no blockages occur inside the main line. The level of fullness is taken into account when choosing pipes for the construction of a discharge system.

Sewage slope for 1 meter: SNiP and standard system parameters

The following formula is used for calculations:

H = V / D, Where:

  • H – the level of fullness;
  • B – level of height of drains;
  • D is the diameter of the pipes.

The maximum value of the level is 1. In this case, the slope of the internal sewage system is completely absent, and the degree of filling of the pipe is 100%. The best option for placing the system is an indicator of 50-60%. At the same time, the material on the basis of which the pipe is made, as well as its angle relative to the local sewage treatment plant – a septic tank – is of considerable importance.

Products made of cast iron or asbestos cement have a rough surface. The presence of the texture on the inside of the pipes ensures fast filling. The main purpose of such calculations is to establish the maximum permissible rate of flow in stock. According to standard standards, the minimum speed of movement of waste liquid is 0.7 m / s. The minimum permissible pipe filling rate is 30%.

For further calculations on free-flow sewage, the following formula is required:

V (h / d)? ? K, Where:

  • V – the rate of movement of waste within the system;
  • h is the degree of fullness of the pipe (the level of effluent in the lumen of the product);
  • d is the size of the pipe section (diameter);
  • K is a coefficient that depends on the roughness of the inner surface of the pipes and the material of their manufacture, as well as the hydraulic resistance affecting the flow.

Sewage slope for 1 meter: SNiP and standard system parameters

For polymer pipes, the reference factor is 0.5. Other materials correspond to the indicator of 0.6. In practice, the consistency of effluent and their quantity are not constant values. Therefore, it is not always possible to accurately observe the sewage flow rate and the speed of movement of the water flow.

Helpful advice! If it is not possible to perform calculations due to the lack of accurate data on the above formula, for the construction of areas that are not amenable to calculation, you can use the minimum angle of inclination. It can be obtained by using the formula: 1 / D, where D is the size of the outer diameter in millimeters.

The optimal diameter of pipes for arranging domestic sewage systems is 40, 50 and 60 mm. In contrast to the SNiP, the current set of rules, which was approved in 2012, does not impose restrictions on the maximum angle of inclination of the pipeline. The minimum angle can be viewed in the table. For a pipe with a cross section of 80 mm, the coefficient is 0.125.

Construction of outdoor and storm sewers: SNiP 2.04.03-85 and its requirements

The external sewage system discharges waste fluid from plumbing fixtures installed inside a residential building, and also collects rainwater from the site during heavy rainfall due to the storm system. Most often, asbestos-cement and cast-iron pipes are used for the installation of sewage at the site. Polyethylene products with a corrugated texture are allowed.

Sewage slope for 1 meter: SNiP and standard system parameters

Pipes for the construction of the outer part of the sewage have a large diameter. For their installation, a separate SNiP document is provided with the following requirements:

  • if the diameter of the outer pipe does not exceed 150 mm, then the minimum allowable angle of the line is 0.8 cm per meter of the system;
  • the maximum allowable drainage slope does not exceed 1.5 cm per 1 m of sewerage;
  • if the diameter of the outer pipe is 200 mm, then the value of the minimum slope of the highway will be 0.7 cm per 1 m of sewage.

Storm sewers are installed with a slope of 0.02 cm. Installation of storm sewers is carried out taking into account additional nuances:

  • the type and characteristics of the soil on the site;
  • the average amount of precipitation characteristic of the region where the site is located;
  • total runoff area;
  • places where underground communication systems are located.

Sewage slope for 1 meter: SNiP and standard system parameters

Note! The SNiP permits a decrease in the optimal rainfall inclination by 2 mm per meter of the system, if the terrain conditions do not allow the installation of sewage strictly according to standards.

To install the sewage system was carried out qualitatively, to control the tilt of the system, special tools or devices will be required. They will allow you to measure the angle of the highway and adjust it if this figure does not meet the standards or calculations.

For these purposes, the ideal building level bubble type. And on both sides of the bubble should be placed on three labels, which fix the deviation from the horizon of 1 cm.

The process of installing the pipeline in the desired position is as follows:

  1. The pipe is being mounted with only one end fixed.
  2. The construction level must be installed on top of the fixed side of the element.
  3. Expose the required slope of the pipe, focusing on the level readings.

When the building level bubble stops at the desired level, the pipe should be fixed at the other end in the installed position. As a tool for measurement, the laser level and level of construction will be suitable.

Standards of sewage slope in accordance with the type of device and diameter of pipes:

Device type The distance between the riser and the siphon (without ventilation), m The diameter of the drain pipe, mm The optimal slope of the system
Bidet 0.7-1 30-40 1:20
Washing 1.4 30-40 1:36
Sink 0.1-0.8 40 1:12
Bath 1.1-1.3 40 Half past one
Shower cubicle 1.6 40 1:48
Drain combined type (shower, sink, bath) 1.8-2.3 50 1:48
Pipe for drains from the riser 1000
Toilet no more than 6 1000 1:20
Central riser 65-75


The scheme of the internal sewage of an apartment or private house should include appliances that are sources of drainage. The list of this equipment consists of a toilet bowl, sinks and washbasins, a bathtub or a shower stall, as well as household appliances that connect to the network. Dishwasher and washing machine machine must be connected to the sewer system and plumbing.

For the construction of internal sewage systems, it is recommended to use plastic pipes with a diameter of 110 and 50 mm.

Requirements of SNiP affecting the installation of the waste complex:

  • the slope of the sewage system is selected taking into account the diameter of the central riser pipe, which is already installed;
  • the minimum permissible deviation rate of the sewer pipeline is 3 cm per 1 m. p., provided that the diameter of the main does not exceed 50 mm;
  • The recommended slope of the pipeline with a section size of 1600 mm is 8 mm per meter. drainage.

Note! The sewage system in high-rise buildings is installed in a vertical position. The movement of wastewater is carried out around the perimeter of the inner walls, while in the center of the stream is compressed air. This approach reduces the chance of sewage clogging.

Sewage slope for 1 meter: SNiP and standard system parameters

Recommendations for the installation of domestic sewer system:

  • it is not allowed to rotate the pipeline installed horizontally at an angle of 90 ?, for this purpose it is better to use angle elbows of 45 ?;
  • the use of right angles in the vertical system is strictly prohibited;
  • a slight excess of the gradient is allowed if the pipe is short.

It is not recommended to make changes to the system tilt layout types. This is indicated by the requirements of SNiP.

External sewage is designed for the withdrawal of contaminated drains in the direction of the septic tank. Autonomous types of systems for moving fluid do not use gravity. Contaminated water is transported to a collection tank using a pump. For these systems, there are certain requirements for SNiP, which spelled out the maximum distance available for pumping waste in this way.

Advantages of autonomous sewers:

  • the pressure sewage pipeline runs at a lesser depth than the main line of other types of systems;
  • there is no need for strict observance of the slope standards, since the drains are moved by a pumping station;
  • The system is based on the self-cleaning of the inner walls of the pipe, so problems with blockages are extremely rare.

Sewage slope for 1 meter: SNiP and standard system parameters

The presence of such advantages does not obviate the need for reconciliation with SNiP during the installation of sewage. Regulatory documents contain requirements for the optimal placement of a septic tank and other elements on the site in relation to residential buildings, sources of drinking water and other facilities. Despite the small depth of the pipe, it is necessary to take into account the level of soil freezing in winter.

When working with external sewage taken into account the relief features of the territory. The construction of drainage wells is recommended to be placed at the lowest points of the site. At the same time, the pipe is laid in such a way that the end of the sewer line is not located below the inlet in the septic tank, otherwise the waste water will not be able to get into the storage tank by gravity.

After the work on the installation of internal and external sewage systems is completed, a test report is drawn up confirming the functioning of the system and compliance with the standards. This requirement is spelled out in one of the SNiP 3.05.01-85 applications.

To check the performance of the sewer system, the pipeline should be shed. To do this, at least 75% of all sanitary equipment that is connected to the area to be checked is simultaneously launched. If the installation of the sewage was carried out by the installation organization, it is impossible to do without such an act.

Sewage slope for 1 meter: SNiP and standard system parameters

Data that is recorded in the document:

  • the name of the system to be checked;
  • name of the construction object;
  • name of the general contractor, customer and installation organization, including positions and name of representatives;
  • information from project documentation (drawing numbers);
  • the list of opened by the device at the time of testing and the duration of the test;
  • data on the presence or absence of defects;
  • signatures of the inspection commission.

Installation of sewage can be done independently or using the services of specialists. In any case, it is important to adhere to regulatory requirements and comply with the technology.

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