How to install a septic tank in the country with your own hands

Recommendation points

• What is a septic tank and who mounts it
• Choosing a place for a septic tank
• If the drainage system is installed for the first time on the site
• A septic tank instead of a drain pit
• Drainage piping
• Drainage piping material selection
• Drainage line and its arrangement
• Installation of a sewage treatment plant
• Digging a pit
• Pillow device
• Installing the septic tank in place. Accession
• Filling, refilling and refining
• Operation and maintenance

In this article, we will tell you how to independently install a septic tank on the site, take into account all the nuances of laying the pipeline, connecting and operating this treatment plant.

Equipping a country house with communications implies competent and comfortable wastewater disposal. It is good if the private sector area in which the house is located is provided with a central sewerage system. If not, you need to seriously think about either equipping a waste pit, or installing a treatment plant. The latter is supported by a large number of advantages, while experienced builders are increasingly calling the waste pit a “time bomb”.

What is a septic tank and who mounts it

A septic tank is considered the most effective treatment facility when it comes to a country house that requires an autonomous sewage system. The essence of its work is quite simple, and the range of devices with different functionality is very diverse. But not only this makes the septic tank popular: a wide range of installation services allows the customer not to delve into the process of arrangement at all, limiting himself only to ordering and accepting the work upon its completion.

However, is it worth investing additional funds if the home owner is able to carry out the installation work on his own? The cost of these services is quite high, in addition, many people want to personally control the process of performing work, especially if the conversation comes about expensive communications that are complex in technical execution.

By and large, all work on the installation of a septic tank can be performed by people who do not have extensive knowledge in the field of wastewater disposal and treatment. If you have a firm intention to carry out these works yourself, you can use the detailed instructions below for the installation of a treatment plant “TOPAS-8”, which is a typical model of a water treatment device.

Choosing a place for a septic tank

The first step is to decide on the place where the septic tank will be located. You should focus, first of all, on the overall dimensions of the device. In our case, a plot with dimensions of 2.4×2 meters is required, where a pit will be dug. The dimensions of the pit may vary depending on the size of the unit itself. It is also worth considering the allowance for the backfill – at least 0.4 meters on each side.

If the drainage system is installed for the first time on the site

At the design stage of the drainage system, the placement of the septic tank can be arbitrary. It is best to install it at the maximum distance from the house, observing the main requirement: the sewer pipe, through which the drains will flow into the structure, should have as few turns as possible and the optimal slope. Each septic tank has a manufacturer-specific maximum insertion depth. This indicator should be relied upon when choosing the distance from the house to the treatment plant so that the end of the pipeline does not fall below the permissible level. The requirements for the location of the drainage outlet in the ground are regulated in some detail by section 2.04.04–85 of SNiP. In any case, you should not place a septic tank closer than seven meters from the foundation of the building: this can lead to partial subsidence of the soil and a decrease in the strength of the main structure of the building. It is also worth knowing that the higher the input is made in the receiving chamber of the septic tank, the greater the volume reserve it has during a salvo discharge, and the less likely it will be to block the drains in the supply pipe.

A septic tank instead of a drain pit

It is clear that you should not place a septic tank in an existing drain well: the work is dirty, and the characteristics of the drain pit do not meet the requirements. If the pit is located at a distance of more than 15 meters from the house, it is better to install the septic tank “in the gap” of the existing system. It is worth keeping a distance of 4 meters from the drain pit to the location of the cleaning device. This placement of the septic tank will allow you to avoid the use of devices for forced drainage of purified water and not worry about the arrangement of a place for its discharge. If the drain pit is located close to the house, the sewer riser should be extended, and a pipe should be laid from the location of the septic tank through which the waste liquid will go into the ground by any of the available methods.

Drainage piping

In any case, it will be necessary either to lay a new sewer pipe, or to correctly position an existing one in the ground. Much depends on this stage of work, first of all – the uninterrupted operation of the treatment plant.

Drainage piping material selection

The pipe material is selected based on the characteristics of the soil and the personal preferences of the owner of the house. You should not use cast iron pipes, unless such a pipe has already been laid. Today the market is very rich in elements of drainage systems made of various materials, but the longest service life is characterized by plastic or composite pipes with a non-adhesive inner coating. If the soil is soft and not exposed to strong mechanical stress, this type of drainage channel will be optimal. The diameter of the pipe depends on the required throughput and filling. At the point where the pipe is connected to the septic tank, a transition to a PVC pipe of the corresponding diameter must be made. For ease of installation, it is better to use a compensation adapter. Do not forget that exhaust gases are ventilated through the inlet drainage channel, which requires a fan riser connected to the highest point of the sewer and brought out to the roof of the building.

Drainage line and its arrangement

The main feature of the trench in which the drainage pipe will be placed is its absolutely flat plane. In order to make calculations, you need to rely on the slope level selected in accordance with the standard. In our case, this is 2 cm of slope per 100 cm of pipe span. Accordingly, with a pipe length of 18 meters, the total slope will be 36 centimeters. The trench is dug in two stages: in the first stage, the soil is removed evenly along the entire length and the general horizontal level, in the second stage, the required depth of the pipe is provided. The depth of the trench must be at least 0.7 meters. When the excavation is finished, the surface is leveled with a bed of sand, granite screening or gravel chips. The evenness and uniformity of the slope are determined by a tight thread or rule. After laying, the pipe is completely covered with a mixture of sand and soil and watered abundantly with water.

Installation of a sewage treatment plant

At this stage of work, it will not be possible to completely manage on our own, with all the desire. The average weight of septic tanks is about two hundred kilograms, and therefore it is worth finding two or three assistants to install the unit itself in place.

Digging a pit

The largest part of the cost of services of installation organizations is enclosed in land works and soil planning. If you have a day of free time, these additional costs can be avoided, because digging trenches and pits is not such a difficult task. The top fertile soil layer, as a rule, is distributed over the land plot, leaving a small part of it for the finishing backfill. The extracted clay does not provide any benefit, so it is worth considering methods for its removal. The pit is dug by the usual manual method, with layer-by-layer soil removal. The walls do not need to be fixed, but it is important to observe the correct geometry of the pit. In most cases, you can take an additional stock in size, if you are not too lazy to dig in excess. For example, with the overall dimensions of a septic tank of 1.6×1.2×2 m (length, width and height of the device), the pit should be dug 2×1.6 in size with a depth of 2.3 meters.

Pillow device

It is better to install the septic tank on a solid base that is not capable of significant subsidence. For this purpose, the bottom of the pit is covered by 100 mm with well-packed gravel or fine crushed stone, followed by backfilling with sand. The level of the cushion must comply with the requirement for the placement of the outer part of the septic tank: the structure must protrude 150–170 mm above the ground, and it is necessary to take into account the subsequent change in the landscape if asphalt or paving slabs are laid. The sand layer must be strongly compacted and aligned horizontally.

Installing the septic tank in place. Accession

Textile straps should be used for installation, but can be replaced with vehicle tow straps. The bandage is passed under the bottom of the septic tank, the latter is subsequently gently and carefully immersed on the bottom of the pit, after which it is leveled with a maximum deviation of 5 mm. The septic tank should be turned in advance to the drainage inlet with the side where the storage chamber is located.

On the same side, markings should be made for the hole: attach a piece of pipe of the diameter used to the wall of the case in the right place and circle it with a thin marker. Next, you need to check the compliance of the marking with the position of the pipe in the ground. If everything is correct, an opening is cut out in the plastic body that has the maximum correspondence to the pipe profile. It is better to cut a hole of a smaller diameter, gradually bringing it to the desired size: the end of the pipe should enter the septic tank very tightly. For sealing, a technical hair dryer and a PP-7 soldering rod are used, it is better not to use synthetic sealants for this purpose.

The sewage pipe is connected to a standard branch pipe with a diameter of 110 mm or 25–32 mm for septic tanks with natural and forced drainage, respectively. To power the compressors and airlifts, a copper cable of the VVG brand is used, without connections, with a cross section of 2×2.5 mm², tightened into a protective sheath in the form of a smooth polyethylene pipe, sealed at the joints. It is better to lay the cable to the power source along the finished drainage trench, and connect it to the septic tank in the junction box of the device. Wiring diagrams must be specified in the operating manual.

Filling, refilling and refining

When the septic tank is installed and connected, it should be filled with water by one third. The gaps between the walls of the pit and the septic tank are filled with sand, which is lightly rammed and poured with water to shrink. Filling the septic tank with water and backfilling the pit should be carried out simultaneously and at the same level. Only this method of installation is able to forestall the “squeezing” of the septic tank from the ground during operation. The last 25-30 centimeters of the foundation pit and trench should be covered with pre-prepared black soil. When constructing a road surface, at the location of a septic tank, avoid placing a common slope point for rainwater drainage.

Operation and maintenance

Most household septic tanks are very unpretentious in the maintenance process, although the established requirements should be met systematically. First of all, it is the need for periodic cleaning and removal of waste sludge. In addition, the operation of the septic tank must be monitored in order to notice a potential malfunction in time and eliminate it in time..

As a conclusion, it can be noted that a septic tank, today, is the most convenient and versatile treatment facility, which allows you to avoid a lot of trouble associated with pumping and disposal of wastewater..