How to dig a septic tank if groundwater is close. How to make a septic tank if groundwater is close enough on the site? Installation of a mechanical septic tank

Sewage at high groundwater levels must be carried out especially carefully, because it is necessary to achieve absolute tightness of the structure. To do this, all connections must be made in such a way as to ensure high protection from leaks. For this purpose rubber and silicone seals. In addition, pipes are not simply inserted into the storage tank, but welded using a welding gun. Construction of a pit for wastewater in conditions of high groundwater level is quite difficult, because it is necessary to constantly pump out the water coming from the ground.

Installation of sewerage at high level groundwater is fraught with the following problems:

If errors are made during construction, wastewater can spill over the surface of the earth around the structure during seasonal floods and during a large volley discharge.
If the autonomous sewage system is not installed correctly, the wastewater can pollute the soil and water supplies. In this case, neither the filtration well nor the filtration fields will help sufficiently purify wastewater.
Due to the fact that the wastewater will not filter well into the soil, an unpleasant odor will constantly emanate from the structure. Its intensity will depend on weather conditions: ambient temperature and atmospheric pressure.

Price issue

To make a sewer system in conditions of high groundwater level, you can always go two ways:

Spend a lot of money at the beginning of installation, installing a bioseptic tank and choosing high-quality LSU pipes for arranging external sewerage. But in the future you will be able to live without problems and not spend anything on maintaining the system.
If you cannot afford to spend a lot at the beginning, then you will have to spend money little by little, but almost constantly. You can save additional money if you do everything yourself. But it is quite difficult to carry out installation correctly in such difficult conditions without the appropriate knowledge and experience.

Autonomous sewerage in conditions of high groundwater level can be done with different options cleaning. The cost of the entire structure also depends on this. So, you can choose one of the following designs:

Bioseptic is the most expensive and most effective option. Degree of purification Wastewater reaches 98%, which is ideal for areas with high groundwater.
Can be done septic tank with mechanical cleaning . But its effectiveness depends on the number of cameras. For these conditions, a three-chamber option is suitable. However, even after such a construction, the wastewater needs additional treatment, which is directly related to the characteristics of the soil.
Storage containers closed type - These are sealed, inexpensive structures that can be used in conditions of high standing soil water. But such containers must be regularly cleaned using a sewage disposal machine, which entails constant costs.

Important: the main condition for sewerage, which is carried out in an area with high groundwater level, is the tightness of the entire structure, regardless of the choice of cleaning method.

Construction of a cesspool

If you want to make an inexpensive autonomous sewage system, then a cesspool - suitable option. In fact, it is a sealed well made of concrete rings or a plastic container with a lid and a hatch on top for pumping out sewage. The main advantages of this option are reasonable price and ease of arrangement.

But such a structure has more disadvantages than advantages:

If the structure depressurizes, the wastewater will enter the soil and groundwater and cause contamination of sources drinking water. This is especially true if a well is used as a source of drinking water on your property and neighboring areas.
Since it is necessary to call sewer trucks to service the cesspool, there must be free access to the structure.
Additional costs for calling a car every 2-4 months.
Even a sealed well made of concrete rings will emit an unpleasant odor when filled with wastewater.

As a rule, the bottom of the cesspool should be no closer than one meter from the groundwater level. However, if this cannot be achieved in conditions of high standing water, when installing an autonomous sewer system, you should adhere to the following rules:

It is necessary to install infiltration cassettes near the structure. These are tunnels with different diameters that can draw in and filter water. Their only drawback is freezing in winter. To prevent this from happening, the cassettes must be insulated.
You can make two storage wells. In the second of them it is installed additional pump, which will pump treated wastewater into a roadside ditch, which should be located at the same level as the site.

Important: on sandy loam and sandy soils with average groundwater level, underground filtration systems can be used. This is a more economical option.

Typically, pit installation in conditions of high groundwater level is carried out according to the following scheme:

To begin with, two pits are dug. In each of them, a sealed structure made of concrete rings or other material is installed. Both tanks are connected to each other by a pipe.
Connects to the main pit sewage pipe walking from home.
Now we are making a device for collecting water from the soil. To do this, we dig a separate hole no more than half a meter deep. We place an infiltration cassette in it.
To pump wastewater from the second chamber into the infiltration cassette, a drainage pump is installed.

Attention: do not install the drain pipe directly into a pit with an infiltration cassette. With such installation, the service life of the system and its functionality will be reduced.

Septic tank with mechanical cleaning

As we have already said, with a high level of groundwater level, the septic tank must be made of several chambers - better than three. In addition, it is better to choose special rings with locks and carefully seal the joints of the structure. Otherwise, effluent from the septic tank may leak into groundwater and cause their pollution.

To create a more airtight and reliable structure, it is better to cast the structure on site. To do this, do the following:

After digging the pit, installation is carried out removable formwork. To dig a pit, it is better to choose a period when the groundwater level is minimal. This happens in winter. But even in hot, dry summers you can dig a pit.
A reinforcement cage is installed inside the formwork.
Then the solution is prepared and poured between the formwork panels. In this case, the pouring is carried out in layers of 25-30 cm, followed by compacting each layer with a deep vibrator or piercing it with reinforcement. This way you can get rid of air bubbles and make the structure stronger, tighter and more durable.
If the depth of the structure must be significant, you do not need to dig a hole to the full depth. After making concrete walls of small height (for example, 1 meter), the formwork is removed and the soil between the inner walls and under them begins to be removed. Thus, the entire structure will slowly sink into the hole. Then the formwork is reinstalled on the recessed walls and concrete is again poured over the reinforcement frame.

Tip: instead of concrete rings for arranging chambers, you can use sealed ones plastic containers. But they need to be carefully fixed in the pit so that they do not float up during floods. To do this, a concrete pad is installed at the bottom of the pit. And the containers are tied with cables to the reinforcement outlets from the concrete bottom.

After completing one chamber, the second and third chambers of the septic tank are constructed in the same way with mechanical cleaning. In this case, all chambers are made with a bottom. Then we install the infiltration tunnel. It may be located almost below the surface of the earth above the ground level. Its installation takes place in the following sequence:

First, we dig a pit 0.5 m deep.
Then at the bottom we make a filter layer of sand and crushed stone 30 cm high.
We place infiltration cassettes on it.
We connect them to the septic tank and fill the hole with soil.
Pour a mound of soil on top to additional insulation infiltration tunnel.

Important: the small diameter of the tunnel (150 mm) allows it to be used even with high groundwater levels. That is, the structure will be almost at the surface of the earth. However, shallow cassettes, in addition to insulation, need to be covered with a hill of earth from above. This way you will reliably protect them from freezing in winter.

The operating principle of a septic tank at high groundwater levels is as follows:

Wastewater flows by gravity into the first chamber of the septic tank. Here, insoluble heavy substances fall at the bottom in the form of sediment. In this case, fats float to the surface and form a film there.
After this, the treated waste flows into the second chamber. Here, further purification is carried out thanks to the activity of anaerobic bacteria that do not require oxygen. They break down the complex organic components of wastewater into simpler elements - water and gas. To remove gases from this chamber, ventilation is provided in the design.
Then the wastewater flows into the third chamber, where it settles and clarifies.
After this, the clarified liquid is pumped into the infiltration tunnel. Here the wastewater undergoes additional purification and is discharged into the ground without the risk of causing groundwater pollution.

The submersible pump in the last chamber of the septic tank must be equipped with a float mechanism so that the unit can turn on and off when the chamber is filled and emptied. It is necessary to lay a connection to the septic tank electrical cable and think over the mounting system for pumping equipment.

The installation of an autonomous sewer system in a private house with a high groundwater level (GWL) requires high level seal the tank so as not to harm your health and the environment. Therefore, it is impossible to do without increased requirements for sealing and additional seals. To improve the quality of sealing during deep water treatment, seals are not simply inserted, but welded into the pipeline sewer system private house.

Installation of sewerage in a private house

Before you start constructing residential and household buildings on the site, you need to consider the location of the autonomous sewer system, including the following nuances:

depth of ground flows;
how to install water supply if groundwater is close;
how many devices are planned to be connected to the system;
calculate the volume of the barrel for sewage;
decide on the material from which the tank is made.

Groundwater level

To determine the groundwater level on the site, you can use the following tips:

The most time-consuming, but most accurate way is to drill a well not far from the planned location for the sewer system;
Interview neighbors who may have more information about the location of the site, the passage of ground flows underneath it, etc.;
If the plot was purchased in a partnership, village, town or private sector under construction, you can send a request to the archive;
If there is insufficient information or no information at all, you should pay attention to the surrounding flora: the growth of certain plants on the site will complement the picture.

Note! In the northern regions of the country, the level of groundwater flows is always higher than in the southern regions.

It is necessary to find out how deep the water flows lie underground before building a house, since the close proximity of underground rivers destroys the foundation of structures over time, and it is impossible to do without draining the foundation.

If underground streams are close

How to make a sewer system with a high groundwater level and avoid mistakes during installation:

Correctly calculate the tank volume. You should not take the minimum values; you need to proceed from the likelihood of a force majeure situation, the simultaneous operation of most or all devices that require connection to the sewerage system (washing and dishwasher, irrigation system and shower use), as well as several tens of liters for the normal functioning of the system. You should not allow the tank to overfill, because... this can lead to unpleasant consequences for:

health of yourself and your neighbors;
local flora and fauna;
foundation of courtyard buildings;
the sewerage system itself (clogged pipeline, etc.).

If groundwater is close, and a chamber is used to drain liquid household waste from plastic, it is necessary to take care of the weighting load, since during floods the structure can simply be pushed out of the pit;
If fiberglass sewerage is used at a high groundwater level, it is not necessary to build a hole under it - fiberglass sewer systems can be installed on the surface of the ground.

What comes out in price

Do-it-yourself sewerage installation can be done in two ways:

spend money first on installing a bioseptic tank, choosing as Supplies SML socketless pipes for water supply;
invest in installing the system at your dacha as little as possible, but be prepared for constant expenses on replacing and repairing parts, more frequent pumping with a suction pump, etc.

According to the cleaning options, there are:

Bioseptics. The most expensive, but practically problem-free option for autonomous sewerage. Waste liquid purification reaches 96-98%. At the moment, the bioseptic is the only station that gives such a result. It is problematic to install with your own hands, since it requires knowledge in connecting alarms, correct connection all devices to a unified autonomous sewage system.

Has a number of disadvantages:

high price;
sludge disposal;
purchase of biological products for liquid purification;
Not all reinforced waste products can be disposed of in a bioseptic tank (prohibition on chemical-containing substances, wool, hair, etc.).

For your information. In addition, the device should not be idle, and therefore it is not suitable as a seasonal station.

Mechanical cleaning system. If groundwater is close to the surface of the earth, it is better to choose the option with 3 chambers. Unlike a bioseptic tank, this device is not capable of providing almost 100% wastewater treatment;
Closed storage tanks - easy to install and inexpensive option, requiring systematic maintenance with sewage disposal equipment.

A cesspool, if the ground flows are close to the surface, will not be suitable, since it is necessary to ensure the tightness of the tank so that liquid waste does not seep into the soil. While the drive is simple sewerage in an area with a high groundwater level, the arrangement of which will not require a large amount of financial, material and labor costs.

What is a drive

A storage tank is a regular tank, whether made of metal, plastic or fiberglass. Firstly, the cost of such a structure, even if made of fiberglass, for 3 cubic meters (which is equivalent to daily use by a family of 3-4 people) does not exceed 18-20 thousand. Secondly, in order to install the tank, you can do without hiring specialists. Thirdly, you don’t need to worry about what goes into the water supply - storage structures don’t care what goes there plain water after a shower, from the bathroom, washing machine or dishwasher; With constant use, the drive can last from 5 ( steel structures) up to 40-50 years inclusive (plastic and fiberglass, respectively).

Take into account! As the sewer tank fills, it is necessary to pump out the concrete waste: depending on the filling rate, you will have to resort to sewerage services several times a year.

If the site is dominated by a high groundwater level, preference should be given to reinforced concrete or metal sewers. If it is not possible to install a system made of reinforced concrete concrete, and the service life of steel fillers is not satisfactory, you can install a fiberglass storage unit on the soil surface or bury a barrel under a plastic sewer (but you cannot do without a weighting agent, since water flows can push the system out).

Note. It is not allowed to line the pit with brick or car tires, since the structure will not be completely sealed.

Where can the water be taken out?

If desired, you can drain water from the sewer tank outside the site. If water flows are located under the ground close to the surface, the ground does not need additional moisture. The liquid can be disposed of independently by laying a drainage system with your own hands:

to the village sewerage system;
the nearest ditch.

There is a more complex option - using a filtration field. However, if you don’t want to pump out the water with a vacuum cleaner, it is better to take the pipe to the local sewer system, since you will have to tinker with the filtration field, because you need to choose a place remote from the septic tank and well: preferably on a slight hill.

How to install an autonomous sewer system

If you need to build a small sewerage system on a site with water drainage, you can equip a pre-prepared cesspool, because all that is needed is to ensure complete tightness of the tank. Having chosen the tank that is optimal in price and quality, you can begin installation:

Dig a second pit near the cesspool;
In each pit, arrange a sealed container (for plastic and fiberglass tanks, it is advisable to make sand cushion so that when lowering the tanks into the pit, the integrity of the tank is not damaged);
Dig a trench between two pits; after laying the pipeline, the pipes must be buried carefully: between the soil and the pipes, make a sand and crushed stone layer, separated by geotextile fabric. This is necessary, first of all, to ensure that the system does not freeze at sub-zero temperatures;

Construction of sewerage and treatment facilities at a dacha or personal plot requires taking into account many little things and nuances that at first glance seem insignificant. An example of such a factor is the groundwater level (or abbreviated GWL) in the area where the a private house or cottage. If they lie deep, then everything is fine, one less problem. But not all areas are in such favorable conditions– in some the groundwater level is 0.5-1 m. In this case, when installing a treatment plant, it is necessary to solve a whole range of problems, and the design of a septic tank for a high groundwater level has its own characteristics and differences. And every owner of a dacha or cottage should know about this.

Problem of high groundwater for sewerage

Let's start with what problems and difficulties for the sewerage system are created by groundwater lying only 0.5-1 m from the ground level.

Flooding– due to soil heaving and groundwater movement, there is always a risk of moisture penetrating from the ground into the septic tank. This problem is especially acute for composite structures made of concrete rings, whose tightness leaves much to be desired. As a result, the tanks quickly fill up with liquid, and it becomes necessary to call a sewer truck. And in the worst cases, flows of groundwater mixed with fecal matter from the septic tank will flow into the sewer system, and then into the house, flooding the bathtub and toilet.
Ascent– this problem is typical for lightweight structures made of plastic cubes. In the spring or after heavy rains for many days, the soil is saturated with a huge amount of water, which puts pressure on it, trying to squeeze it up. In this case, the septic tank itself turns into a kind of “float”. And if the tanks were not securely fixed to the concrete pad, then they will begin to float upward. Often this phenomenon is accompanied by tilting, leakage and sewerage breaks. As a result, the treatment system has become unusable, part of the site is flooded, and fecal matter penetrates into groundwater.
Drainage- one of the most important stages sewage treatment is ground tertiary treatment. Water, having passed through the septic tank tanks, enters special filtration fields. There it, seeping through a bed of gravel, enters the soil, where it undergoes the last and most important stage of purification. According to sanitary standards, there must be a layer of earth at least a meter thick between the water supply and the filtration field. Accordingly, meeting these requirements with groundwater lying at 0.5-1 m is quite problematic. Ignoring these standards leads to pollution of surrounding ponds, rivers and wells.
Waterlogging– soil in a zone with high groundwater level is characterized by high humidity. Consequently, the ability to absorb water for post-treatment will be worse. And if this factor is not taken into account, the land around the septic tank will turn into a small swamp.
Damage to the septic tank– groundwater is often characterized by increased alkalinity or, conversely, acidity. In such cases, they not only put pressure on the walls of the tanks and penetrate inside when the seal is broken, but also gradually destroy them. This is especially true for concrete structures. In addition, groundwater is not static, it is in motion and often carries with it small and sharp stones, which can also damage the integrity of septic tanks or connecting pipes.
Installation problems– one of the main problems for the construction of treatment facilities in areas with high groundwater levels. When digging a pit, builders will be forced to work knee-deep in water. In addition, the process of pouring concrete or installing industrial septic tanks becomes more complicated.

Important! The danger of sewage seeping into the ground, mentioned several times above, is that groundwater is constantly moving and mixing. And if fecal matter, sewage and harmful microorganisms get into them somewhere, then they spread over a large area. As a result, the soil and groundwater become polluted, and nearby wells, streams and ponds become poisoned and undrinkable. In fact, a local environmental disaster occurs, caused by errors in other treatment systems.

Determining the depth of groundwater

You know about the problems that arise with high groundwater level. The next step is to determine the depth of groundwater in your own area.

The list shows three ways to do this, listed in order of increasing difficulty:

survey of neighbors;
search for indicator plants;
drilling of exploration wells.

The second way is to evaluate what grows on your site and in the surrounding area. Plants are a kind of indicators that allow us to draw approximate conclusions about the groundwater level. If the flora in the area is predominantly moisture-loving, then most likely the groundwater level here is high. For more precise definition use the table.

Table. Indicator plants indicating the groundwater level in the area.

Approximate groundwater level, m	Indicator plants
From 0 to 0.5	Sedge, cattail, reed, Langsdorff's reed grass, marsh wild rosemary, downy birch
From 0.5 to 1	Canary grass, meadowsweet, cattail, reed,
From 1 to 1.5	Sandy rush, spruce, heather, blackberry, mouse pea, white bentgrass, meadow rank and fescue
From 1.5 and deeper	Yellow alfalfa, naked licorice, chi, meadow clover, awnless brome, plantain, creeping wheatgrass, juniper, moss, lingonberry

The third method is the most accurate, but at the same time the most labor-intensive. Let's present it in the form of step-by-step instructions.

Step 1. Prepare a drill with a length of at least 2 m. If necessary, you can use a tool with a greater drilling depth.

Step 2. Identify several locations on the site for wells. It is advisable that one of them be located where the installation of a septic tank and treatment systems is planned.

Step 3. Drill a hole 2 m or more deep.

Step 4. Wait a day. To be safe, cover the tops of the wells with waterproof material so that overnight rain does not interfere with the determination of groundwater level.

Step 5. Prepare a metal pin or wooden stick for the depth of the well. Place marks on its bottom every 10 cm.

Step 6. Immerse this “indicator” into the well and pull it out. Determine the length of the pin that was wet and determine the groundwater level. As an example: a well was dug 2 m deep, the pin turned out to be 30 cm wet. Make simple calculations 200 – 30 = 170 Therefore, the groundwater level in this location is 1.7 m.

Step 7 Wipe the “indicator” or let it dry and repeat the experiment with other wells on the site.

Step 8 Repeat steps 6 and 7 with all wells for three days to obtain a more or less accurate result.

Important! It is best to take measurements in the spring, after the snow melts, when groundwater rises to its maximum. If waiting until March or April is too long, try the experiment in the summer or fall after several days of heavy rainfall.

What should a septic tank be like for a high groundwater level?

Let's consider the basic requirements that each plant placed on an area with a high groundwater level must meet.

Video - Construction of a septic tank on an area with a high groundwater level

Monolithic concrete septic tank - instructions

One of the most common designs created independently for country house or cottage. The walls and bottom of septic tanks are reinforced with lattice and have sufficient strength not to collapse under the pressure of groundwater and earth outside. Due to heavy weight cannot emerge in the spring or during the rainy season. In this case it will be considered step-by-step instruction to create a three-chamber monolithic concrete septic tank, providing a significant degree of sewage treatment.

Step 1. Determine the place under), its dimensions, then start digging a pit. Depth – 3-3.5 meters. If possible, order the work of an excavator or a team of excavators - in this case, you can dig a pit on the first day. To prevent the walls from crumbling, lay them out plastic film. Compact the bottom of the pit.

Important! Additionally, it makes sense to build an awning over the pit so that it does not get flooded with rain. In order to minimize the problem with groundwater, start installing a septic tank in the summer during the driest period. If moisture still accumulates at the bottom of the pit and interferes with work, place a hose from the pump there.

Step 2. Place a compacted and moistened sand cushion 15-25 cm deep at the bottom.

Step 3. Proceed with the construction of the external formwork. Use fairly thick and strong boards, as a large mass of concrete will be poured. If the formwork is too weak, it can simply push it to the sides, especially in the lower part of the monolithic septic tank. Don't forget about the timber spacers.

Step 4. Start forming a reinforcing lattice on the bottom and walls of the pit. Use steel rods with a cross-section of 10 mm, tie them together with wire. The side of each individual lattice cell is from 20 to 30 cm.

Step 5. Form a reinforcing grid on the partitions that will divide the septic tank into separate chambers.

Step 6. Fill the bottom of the pit with concrete; the thickness of the bottom of the septic tank should be at least 150 mm. Add anti-corrosion and waterproofing additives to the mixture so that the tank does not allow groundwater to pass through and is not subject to destruction due to the aggressive internal and external environment.

Step 7 Build internal formwork that will form the walls of the septic tank and divide it into three separate chambers.

Step 8 Start pouring external walls and septic tank partitions. Don't forget to create overflow holes from chamber to chamber. When pouring, try to reduce the number of cold seams, as they will be the weak points of the structure, where leaks will occur first.

Step 9 Build the formwork for the roof of the septic tank. In this case, the boards must be carefully adjusted to each other. Don’t forget about hatches and ventilation - each septic tank chamber should have its own hatch for inspection, Maintenance and, if necessary, sewage disposal.

Step 10 Fill the ceiling with concrete, which will be the roof of the future treatment plant.

Step 11 Separately form a reinforced lattice around the hatches and fill them with cement mortar.

Step 12 Install tees for overflow holes inside, fill the septic tank with soil on top, install manhole covers and a ventilation system.

The three-chamber monolithic concrete septic tank is ready. Next, all you have to do is make a diversion from it to an embankment with a filtration field (for post-treatment process water) or to the gutter.

A two- or three-chamber septic tank made from Eurocubes is constructed using a similar principle. In this case, it is necessary to take into account the high level of groundwater and, accordingly, the danger of floating. Therefore, plastic Eurocubes are mounted on a previously poured or laid anchor concrete slab. It also makes sense to protect the structure from the sides with something from compression during soil heaving.

When using an industrially made septic tank, such as or, the same recommendations apply - a concrete slab is installed at the bottom of the pit under the treatment plant, the tank itself is fixed to it using anchor straps, as in the image below.

If you consider yourself not very knowledgeable in construction and have doubts, then it is better to contact an experienced specialist who has encountered similar problems and knows the solution when installing both a homemade and industrial septic tank. Remember one important truth: when landscaping a site, money is spent either at the construction stage or after it, but on correcting mistakes and combating the consequences of savings at the expense of reliability.

Prices for anti-corrosion and waterproofing additives

anti-corrosion and waterproofing additives

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We have long been accustomed to communal comfort and convenience. And such ordinary things as the sewer system are taken for granted. Any country house is equipped, as a rule, with the benefits of civilization. In addition, every average citizen can build at least a primitive sewer system. But this is not always and everywhere easy to do.

Most of Russia is in such climatic zone, where high groundwater levels are the number one problem. It is not easy to build a sewer system in such conditions. There is a high risk that wastewater will end up in groundwater. Or vice versa - the septic tank will be “sunk” by groundwater. You can, of course, buy a sealed plastic tank. But you will have to call the vacuum cleaner often.

Or you can save money and build a septic tank yourself, specifically designed for such an area. After all, sewerage with a high groundwater level is a completely solvable problem (more details: " ").

Features of sewerage design if groundwater is close

Let’s make a reservation right away: sewage systems with a high groundwater level are, in principle, built in the same way as a completely ordinary one. So what is the “highlight” of such a septic tank? A cesspool without a bottom is erected above groundwater (more details: ""). It is obvious. Next, infiltration tunnels are installed in the structure (they are also often called “cassettes”). Tunnels are also located above groundwater. It is important to know how to insulate a septic tank, if this is necessary in a particular case.

The liquid that has passed all stages of purification flows from such tunnels into the soil layers without polluting them or harming the surrounding environment. The diameter of the infiltration tunnels is small. Usually it is approximately 130-200 mm. They are placed even on the very surface of the earth, without burying them. This is especially true if the groundwater level is excessively high. However, in the cold season, these pipes will have to be properly insulated. Otherwise, there is a high probability that they will simply freeze and stop functioning as usual.

The principle of operation of the sewage system

Let's look at how sewerage works with a high groundwater level. First, wastewater flows from the house through a pipe directly into the first tank. There their initial rough cleaning takes place. The drainage then flows through the connecting pipe into the second tank. Here, anaerobic fermentation of the contents occurs, resulting in more thorough cleansing drain water. And finally, the third tank. In it, the incoming liquid becomes more transparent and clean, all remaining particles settle to the bottom.

After the wastewater passes through such a three-chamber sewage system, it flows into the infiltration tunnel already mentioned above. This happens thanks to the action of a submersible pump.

In such a tunnel, the wastewater undergoes final purification and is discharged into the soil itself.

This is the principle on which sewerage works when groundwater is high. In principle, you can contact specialized companies for the installation of such a system. However, if you have the desire and skill, you can easily get by on our own. It turns out that this is a feasible task. Therefore, we will consider the question of how to make a sewer system - if groundwater is close with our own hands.

Features of sewerage construction at high groundwater levels

It is important to know that the construction of a sewerage system should begin only when the groundwater level drops to its minimum. Only after this should you start digging a pit. There you need to place two wells. Either you will have to install the sewer well yourself, or you can buy industrial plastic tanks. One of the wells must be connected to a sewer pipe coming from the house. And the second is connected to the first well through a pipe, but in such a way that liquid from the first flows easily into the second.

In general, if you have doubts about what materials to build wells from, then you should opt for reinforced concrete. By the way, you can also find ready-made wells for installation on land plots for sale. True, you will have to pay a lot for this. Plus, consider the cost of delivery and installation of such wells.

As for the infiltration tunnel, the installation of a sewer system at a high groundwater level cannot do without it. It is better to place this cassette tunnel at a depth of up to half a meter in the ground. If the groundwater is too close to the surface, then pour sand into the channel dug under the cassette, lay a layer of crushed stone on top, and then the infiltration tunnel itself on top of it. Do not forget that the cassette must be properly insulated. Place gravel and sand on top. You can also consider laying a special heat-preserving material over the infiltration tunnel.

In general, it is better to buy an infiltration tunnel ready-made. But you can do it yourself. This tunnel is an elongated plastic box. In some ways there are similarities with a regular pipe. This cassette tunnel is equipped with many technological holes through which water will seep into the soil. By the way, you can purchase a cheaper replacement. This is a foundation drainage, which is also equipped with holes. It may well perform the functions of an infiltration tunnel, but still the effectiveness of its work will be much lower. Therefore, when making a choice, proceed from your financial capabilities and how long you want the sewer system to serve you.

Also keep in mind that the infiltration tunnel (or simply the infiltrator) cannot be operated alone, without working together with the septic tank itself. In other words, taking and burying an infiltrator in the ground and pouring wastewater into it directly, without cleaning, is an absurd solution. Indeed, in this case, the holes of the mechanism will immediately become clogged. And it will either have to be thoroughly cleaned or replaced with a new one. So don't take risks. And follow all the rules.

And finally, the last element of the entire system. This is a pump. The submersible pump is attached to the last tank of the sewer system. It must have a float that will control the filling level of the container and give a signal to automatic switching on pump Experts advise purchasing two submersible pumps. The thing is that, as a result of force majeure, one of the pumps may not work, then the second one will definitely save the situation.

This is how sewerage is built - if groundwater is close. Of course, this cannot be said that this is an easy and simple way to equip the system. But perhaps this is the only way out. Do not forget that if your area suffers from a high level of groundwater, you will have to work hard to get the treatment system working. But if you follow our advice and thoroughly work through this problem, then autonomous sewerage with a high groundwater level it will work smoothly, like a clockwork. This means that all you have to do is enjoy the result of your work and comfort. country life with all public amenities!

For sewer system equipment in country houses where it is not possible to connect to a centralized system, it is necessary to install local treatment facilities or a septic tank. The second option is the most profitable from a financial point of view, so many people choose it. However, during installation you may encounter one serious problem - a high groundwater level (GWL). As a result, a logical question arises - how to make a septic tank if groundwater is close?

Installation of a septic tank on the site

Why is it important to consider groundwater level?

If the water is near the surface of the earth, this means that when deepening the septic tank, the use of special construction methods aimed at ensuring the stability of the structure and preventing depressurization of connections. IN winter period another danger arises - freezing of the soil and, as a result, the occurrence of heaving, which can cause deformation of the storage tank. That is, the wastewater will fall into the ground, and then into the water layer and pollute environment, which is unacceptable.
During spring floods, reservoirs can flood the surrounding area and the septic tank can float up. The result is the same as in the previous version, only the sewage will also pollute the reservoir. It can also rupture plastic sewer pipes and have to be replaced. In the worst case, the septic tank will remain in the ground, and water will flood it from above, as a result of which sewage will flow back into the house in the absence of an installed check valve.
Septic tanks with leaking structures must not be used. This is especially true for the use of cesspools or septic tanks in the form of concrete rings. Firstly, its construction will require financial costs comparable to a sealed septic tank made in industrial conditions, and secondly, this is contrary to sanitary standards.
Depending on the ground level, it is necessary to apply special design measures to ensure maximum protection to prevent environmental disaster.

How to accurately determine groundwater level?

Usually measurements are taken in the spring, when the water rises to the maximum possible height after the snow melts. Take an ordinary garden auger and do vertical hole in the soil to the surface of the water, and then their depth is determined. If the septic tank needs to be installed promptly, then you can use geological survey data, which will reliably show how the water layer passes under land plot. Another less informative way is to find out the necessary information from old-timers, but you should not always trust it.

preparing pits for installing a septic tank

Is it worth making a septic tank yourself?

Despite the apparent simplicity of the septic tank design design work according to his calculations, selection of strength and performance characteristics is a task for professionals. However, their cost turns out to be several times more expensive than homemade ones. The difference between them will be significant and will be as follows:

The finished structure will ensure maximum tightness due to the adjustment of all parts and the use of stiffeners that can prevent any loads within the specifications. Evaluation homemade system it will be very difficult to evaluate, so it is unknown how it will behave in a particular situation.
An industrial septic tank is equipped with all the necessary filters, is able to cope with specific loads and meet sanitary standards.
Ready-made septic tanks have not only a high level of protection from external mechanical, but also from internal chemical influences, while ensuring stable operation during the warranty period. Homemade design cannot guarantee the absence of leaks into the ground or a sufficient degree of purification when using filtration fields.

Therefore, before making a decision on choosing a septic tank of a ready-made design or installing your own, you need to weigh everything and make the only right decision.

installation of a concrete septic tank from rings

If you do not have the necessary experience, you should contact a specialist who can analyze the soil or existing data and select the most suitable design according to the parameters.

What requirements must a septic tank meet?

have complete sealing of the chambers;
have protection against ascent;
have high hull strength.

What type of device should a septic tank have at high groundwater level?

The design of the septic tank must be sealed and consist of one container divided into compartments, or several Eurocubes. The system can be either gravity-flow or forced-injection. The second option should be used only in cases where the installation is carried out in a flooded area and there is a need to place storage tanks above the level of the house.

On inlet pipe need to install check valve to prevent backflow of wastewater. The pipe for discharging purified water should be made at such a level that groundwater does not enter there. Typically, a special sealed compartment or a separate sealed container is provided for this.

Rules for choosing a septic tank with high groundwater level

The volume of the septic tank must be clearly calculated so that under high loads it does not have to constantly remove sewage.
The type of construction is allowed either storage or with pumping of purified water and its effective disposal into the ground.
It is advisable to choose a septic tank material based on durable plastic and steel with a protective polymer coating applied. It is not recommended to use a concrete septic tank at a high groundwater level, since the soil can freeze and there is a high probability of one ring being displaced relative to the second and sewage entering the soil is simply inevitable. An exception may be soils with a dense composition and a minimum level of heaving.
In order to increase cleaning productivity and minimize the amount of waste removal, a multi-stage cleaning system should be organized: from mechanical impurities, chemical disinfection and filtration of purified water with discharge into the ground.

trenches for septic tank system

How to choose a place to install a septic tank?

The installation site must first of all meet sanitary standards:

The distance from a residential building must be at least 5 m.
The distance from sources of drinking water should be 50 m, and from open bodies of water - 30 m.

In this case, you need to take into account the location of the buildings so that they are located at a distance convenient for servicing the septic tank. Also, do not forget that the sewer pipe must run at an angle. The greater the distance from the sewage discharge points, the greater the depth required based on the condition of a slope of 2-3 degrees per meter of length, while in the presence of a minimum groundwater level of up to 1 m, this is simply unacceptable.

When creating sealed containers for wastewater removal, it will be necessary to organize convenient vehicle access for pumping it out.

How to properly install a septic tank?

A septic tank for a high groundwater level must not only be installed on a stable base, but also be firmly fixed to prevent its displacement or deformation of the body in case of weak and moving soils. The base is a compacted sand and crushed stone cushion, which is poured into a specially prepared trench. The size of the trench is usually selected so that its walls have a gap from the walls of the storage tank of at least 30 cm. This is required to minimize the influence of heaving soil layers.

However, if the groundwater level is located at a level of up to 1 m, this will not be enough and it will be necessary to additionally pour a concrete monolith or lay a finished reinforced concrete slab, after which it must be waterproofed and insulated. It will serve not only as a base, but also perform the function of securing when the containers are insufficiently filled, preventing them from floating. Failure to use insulating layers can lead to concrete cracking and loss of strength. Sometimes they install on the bottom drainage pipes to drain water from the trench.

covering the finished septic tank after fixing it with concrete

The supply pipes will also require laying a sand-crushed stone layer to prevent damage in case of possible swelling. After this, you need to install the septic tank and secure it to the anchor straps to concrete base and also waterproof it. The pipes are connected, and then a sand-crushed stone mixture with the addition of dry cement is poured onto the sides of the tank. The dimensions of crushed stone should be up to 5 mm.

At the final stage, pipes for sewer ventilation are installed and the septic tank is filled with earth. Simultaneously with filling, fill the container with water to approximately 1/3 of its volume. The height of the ventilation pipe must be higher than 60 cm above ground level.

What to do if water comes in while digging a trench?

It should be noted that if there is water in the trench installation work is strictly prohibited. Therefore, you should choose one of the options for solving this problem, which are given below:

Use a drainage pump to pump out the accumulated water.
Carry out work in winter. However, do not use a fill as a base. concrete mortar, and ready-made reinforced concrete slabs.
Use the method of above-ground installation of a septic tank with forced injection of wastewater.
Make a sealed one monolithic frame in the form of a box according to the size of the trench.

How to implement a soil-based water purification system?

Since the water level can change dramatically depending on the season, filtration field systems are not always possible to implement. Therefore, special filter cassettes are used, which are placed directly on the surface of the earth or on hills. To do this, remove a layer of soil to a depth of 30 cm and 25 cm larger on each side. A sand cushion 30 cm high is poured onto the bottom, tamped and leveled.

After this they place it around the perimeter concrete blocks, which are secured in such a way that they are airtight. Crushed stone with small fractions is poured into the resulting box, on which the cassette will be directly installed. Then pipes for water supply are brought in, connected to the cassette and the box is closed concrete slab with a hole for ventilation. The hole should usually be installed ventilation pipe so that the smell goes up under the influence of draft, and does not accumulate in the yard. The finished structure is covered with earth and decorated using various landscaping techniques.

If the soil freezes in winter to a depth greater than the height of the earthen layer of the embankment, then the cassette in the upper part should be insulated with foam boards or expanded clay, and it must be completely waterproofed.