How to install a septic tank if the groundwater is close. Cesspool and groundwater

Arrangement of an autonomous sewage system in a private house with a high groundwater level (GWL) requires a high level of tank tightness so as not to harm your health and the environment. Therefore, you cannot do without increased requirements for sealing and additional seals. To improve the quality of sealing with GWL, seals are not simply inserted, but welded into the pipeline of the sewer system of a private house.

Sewerage installation in a private house

Before starting the construction of residential and domestic buildings on the site, you need to think over the location of the autonomous sewage system, including the following nuances:

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

Groundwater level

To determine the GWL at 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 place for the sewer system;
Interview neighbors who may have more information on the location of the site, the passage of soil flows under it, etc.;
If the site was purchased in a partnership under construction, village, town or private sector, you can send a request to the archive;
If there is not enough information or not at all, it is worth paying attention to the surrounding flora: the growth of certain plants on the site will complete the picture.

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

It is necessary to find out how deep the water streams run underground before building a house, since the close location of underground rivers eventually destroys the foundation of the structures, and one cannot do without drainage of the foundation.

If underground streams are close

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

Calculate the correct 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 sewer (washing and dishwasher, irrigation system and use of a shower), as well as several tens of liters for the normal functioning of the system. It is not worth allowing the reservoir to overflow, because this can backfire for:

health of their own and their neighbors;
local flora and fauna;
the foundation of the courtyard buildings;
the sewer itself (clogged pipeline, etc.).

If the groundwater is close, and a chamber is used to drain liquid household waste from plastic, it is necessary to attend to the weighting load, since during floods the structure can simply be pushed out of the pit;
If fiberglass sewerage is used with a high level of groundwater, it is not necessary to equip a pit for it - fiberglass sewerage systems can be installed on the ground.

What comes out for the price

A do-it-yourself sewer device can be made in two ways:

spend money first on the installation of a bioseptic, choosing SML socketless pipes as consumables for the water supply system;
to invest in the installation of the system at the dacha to a minimum, but be prepared for constant expenses for the replacement and repair of parts, more frequent pumping out with a suction pump, etc.

Purification options are distinguished:

Bioseptics. The most expensive, but almost hassle-free option of an autonomous sewage system. Waste liquid treatment reaches 96-98%. At the moment, bioseptic is the only station that gives such a result. It is problematic to install with your own hands, since it requires knowledge of connecting an alarm, the correct connection of all devices to a single autonomous sewage system.

Has a number of disadvantages:

high price;
disposal of sludge;
purchase of biological products for liquid purification;
not all reinforced concrete products can be poured into a bioseptic (ban on chemical-containing substances, wool, hair, etc.).

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

Mechanical cleaning system. If the groundwater is close to the surface of the earth, it is better to choose the option with 3 cameras. Unlike a bioseptic, this device is not able to provide almost 100% wastewater treatment;
Closed-type storage tanks are an easy-to-install and inexpensive option that requires systematic maintenance with sewage equipment.

A cesspool will not work if the soil flows are close to the surface, since it is necessary to ensure the tightness of the tank so that liquid waste does not seep into the soil. While the storage is a simple sewerage system on a site with a high level of groundwater, the arrangement of which does not require a large amount of financial, material and labor costs.

What is storage

The 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 the daily use of 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, there is no need to worry about what is drained into the water supply system - the storage structures do not care whether simple water comes there after a shower, from a bathroom, washing machine or dishwasher; With constant use, the drive can last from 5 (steel structures) to 40-50 years inclusive (plastic and fiberglass, respectively).

Take into account! As the sewer tank is filled, it is necessary to pump out reinforced concrete products: depending on the filling speed, you will have to resort to sewer services several times a year.

If a high level of groundwater prevails on the site, preference should be given to reinforced concrete or metal sewers. If it is not possible to install a system from reinforced 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 cover the pit with bricks or car tires, since the structure will not be completely sealed.

Where can the water be taken

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

to the village sewerage;
the nearest ditch.

There is a more complicated option - the use of a filtration field. However, if you do not want to pump out water with a sewer, it is better to bring the pipe into the local sewer, since you will have to tinker with the filtration field, because you need to choose a place remote from the septic tank and the well: preferably on a small hill.

How to install an autonomous sewage system

If you need to build a small sewage system on the site at the groundwater level, you can equip a pre-prepared cesspool, because all that is needed is to ensure the complete tightness of the tank. Having chosen the tank that is optimal for the price and quality, you can start the installation:

Dig a second pit near the cesspool;
In each pit, equip a sealed container (for plastic and fiberglass tanks, it is advisable to make a sand cushion so that when the tanks are lowered 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-gravel layer, separated by a geotextile fabric. This is necessary, first of all, so that the system does not freeze at sub-zero temperatures;

The proximity of underground sources complicates the arrangement of the sewerage system in a private house or in the country and its maintenance. Problems can arise both during the installation process and during the further operation of highways and a treatment plant. It is worth figuring out how to make an effective sewage system in a private house if groundwater runs close to the surface.

Danger of proximity to groundwater

Difficulties arise already at the time of laying pipes and installing a septic tank. The dug trenches and pits are instantly filled with water, so constant pumping is required.

With further use of the system, there is a risk of water seeping into the cleaning device. If the tank is not tight enough, for example made of concrete rings, it will fill up very quickly. This will require frequent calls to the flushers. If the tank overflows, wastewater will flood the bathtub and toilet.

Overflowing a treatment plant is dangerous:

the appearance of an unpleasant odor;
the spread of infection;
destruction of the walls of the device.

The soil in the area adjacent to the reservoir will eventually become swampy from excess moisture, which will lead to corrosion of pipes if they are made of metal.

Underground springs are rarely perfectly clean. They contain acidic or alkaline substances, which leads to corrosion of the walls of the tanks and their further deformation. Pebbles with sharp edges in the water make the situation worse.

Determination of the level of underground sources

Before installing the sewage system, you should find out how close the water flows are to the surface:

find out from the neighbors;
analyze what flora grows on the site;
drill a well.

The first method is the simplest. If someone in the neighborhood has already equipped the local sewage system with their own hands, he will tell you the level of occurrence of underground sources.

Moisture-loving sedge, cattail, reed, marsh wild rosemary, and fluffy birch speak about the high location of soil streams. If they grow on the territory, the aquifer is only half a meter. Canary grass, meadowsweet meadows indicate a meter depth of occurrence. Where spruces, heather, blackberries, mouse peas, white bent leaves, meadow fescue grow, the groundwater level is about one and a half meters.

These two methods provide a rough estimate of the location of subsurface sources. To clarify the situation, test wells are being drilled.

Stages of work:

In two or three places on the site where the sewerage is supposed to be installed, a well is created with a two-meter drill.
Cover the holes with polyethylene so that possible rain does not interfere with the study.
A wooden stick is marked every 10 cm.
The measuring tool is lowered into the wells one day after their creation and the moisture level is determined. If the "indicator" is 20 cm wet, then the subsurface streams are located 180 cm from the surface.

Test drilling is best done in spring or after heavy rainfall, when soil moisture is at its maximum.

Features of sewerage installation

For a site with closely located water streams, it is better to use a socketless sewage system. The pipeline itself, as well as the treatment plant, must be airtight. It is recommended to use pipes made of polymeric materials that are not subject to corrosion.

Constructions made of concrete rings will not work in this case. But if this is the only option, they should be well waterproofed, all seams should be filled with concrete mortar with hydrophobic additives.

It is better to use plastic tanks to create a summer cottage sewage system in an area with a high groundwater level. They are inexpensive and moisture resistant. Since such devices are lightweight, after a heavy downpour or in the spring, they can float up and break the entire communication structure. To prevent this from happening, they are fixed to the concrete base with the help of anchors.

It is even better to purchase a factory septic tank with multi-stage wastewater treatment. Such an installation is not cheap, but it pays off with a minimum of time spent on its operation and increased reliability.

For flooded areas, the following brands of ready-made cleaning devices are suitable:

"Tank". Consists of several devices made of plastic with a thickness of 1.7 cm, which allows it to withstand heavy loads. Does not float to the surface when flooded.
"Triton". Manufacturers offer several options for reliable septic tanks, but they require anchoring on a concrete base.
"Leopard". The robust design of three chambers with two levels of bioremediation is suitable for areas with sources close to the surface.
Ecopan. Recommended for installation in loams and soils prone to heaving. Holds loads well.
"Tver". A comprehensive cleaning system suitable for wetlands. It brightens drains well, but requires an electricity source.

When choosing a ready-made septic tank for an area with high humidity, you need to check the tightness of the structure, its strength and ease of use.

Selection of treatment design and installation steps

If you decide not to hire professionals and not to purchase a ready-made sewage treatment plant, the device of a local sewage system in a private house with a high level of groundwater involves the creation of a sealed cesspool or a multi-chamber bioseptic.

Sealed cesspool

A sealed sump requires regular pumping

In areas where water flows are close to the surface, it is easiest to install a sealed plastic storage device with a hatch for pumping sewage with your own hands. You won't have to spend a lot of time and money on installation, but the structure will require regular pumping.

It is desirable that the bottom of the structure be at a distance of one meter to the aquifer. If this is not possible, the purification device is constructed as follows:

Dig two holes, one for the size of the container, the other about 0.5 m deep.
A sealed container is installed in a large one and connected with a pipe segment to the second recess.
A sewer line is connected to the main tank.
An infiltration cassette is installed in the second pit, which will draw in and filter moisture. Or install a pump to pump water into the nearest ditch.

The disadvantage of the cassettes is that they freeze in winter. Therefore, the devices are insulated before installation.

Multichamber bioseptic

Bioseptic device

This option is more expensive but more effective. For places where underground sources are located shallow, a device with three chambers is suitable. It is also better to create them on the basis of sealed plastic containers. To prevent them from floating up during operation, you should anchor them to concrete foundations at the bottom.

After the tanks are installed, an infiltration tunnel is created, located near the ground surface.

A trench is dug 50 cm deep and 15 cm wide.
A sand-gravel cushion is created at its bottom for drainage. Thickness - 30 cm.
Infiltration cassettes are laid, connected to a cleaning device and covered with soil.

After burying, it is advisable to pour a mound of earth over the tunnel to insulate the cassettes in winter.

If you are lucky enough to have a site in a swampy area (that is, where the level of groundwater flow is close to the surface), then equipping the sewerage system will become a task for you that requires a careful approach. Since it is impossible to arrange a septic tank for high groundwater with a drainage bottom.

Such an installation of a standard sewage tank threatens a mini-ecological disaster at least for a specific site, and on a larger scale - for all neighbors. Since wastewater, getting through the drainage chamber into the ground, will merge with groundwater, and from there it will be sent to the nearest wells, wells, garden crops, etc.

What is the solution to the problem for the "happy" owners of a summer cottage or suburban area in a swampy area, we understand our material. And for clarity, we attach the video below.

Important: with a high groundwater level (groundwater level) on the site, it is imperative to make an amendment for this factor at the time of design and installation of all communications related to water.

If you understand that a standard cesspool, even for a seasonal dacha, is not your case, since there is a risk of poisoning the entire perimeter of land holdings, then we suggest you understand even more thoroughly the features of a swampy area and understand how difficult it is to install sewage systems. In addition, here you will find out what risks may await at the time of construction and operation of a sealed septic tank for pumping on such soils. As they say, forewarned is forearmed.

So, even the simplest single-chamber design of a septic tank will require remarkable efforts for its installation. And it's all about the mobility of moist soil. Therefore, you have to tinker in order to securely fix the chamber of the treatment plant in the ground. Most often, for this, either a concrete slab is used (if a plastic septic tank is installed), or a cleaning well is mounted from concrete rings. In any case, the installation process will take longer than installing a septic tank on standard soil with a low GWL.
The ascent of the septic tank chamber in the season of melting snow or lingering rains. This is especially true for plastic tanks. The point is that plastic drives are identical to water floats. So, even in a filled state, such chambers are subject to a powerful pressure of soil, sprinkled with water. As a result of the ascent or tilt of the septic tank, the tightness of all joints will be broken. There is a risk of seepage of both dirty water into the ground, which is dangerous for the environment, and groundwater into the chambers of the septic tank, which will require frequent invitation of sewage equipment. And this will hit the family's pocket.
Complete flooding of all chambers of the septic tank. This can also happen as a result of shifts in the tank and a violation of its tightness due to violations of the installation rules. As a result, you will have to face a local disaster. All water sources will be poisoned, ponds and reservoirs may bloom, and garden and horticultural crops will become unusable.

Important: a septic tank for an area with a high GWL must be completely sealed in all chambers. There should be no drainage into the soil.

How to correctly find out the level of groundwater at the site

In order to make sure that your site is located in a swampy area, you should make some observations. As a rule, the groundwater level on the site is fully manifested in the season of snow melting or autumn lingering rains.

To check the groundwater level, you need to drill depressions in the garden at the right time. For work, use a simple auger garden drill. Depressions are made until they hit the water.

Important: it is necessary to make several control grooves at once at different ends of the site. This is done in order to make a reconciliation of the data obtained throughout the territory.

If you don't feel like messing around with drilling and tracking, then you can just chat with your neighbors. The long-livers of your village definitely have information about the groundwater level, which will facilitate the subsequent installation of a septic tank.

Important: almost the entire middle zone of Russia is located in a swampy area. Sometimes the groundwater level can be only 20-40 cm from the earth's surface. This once again indicates that a private sewage system in the form of a septic tank should be extremely tight and only for pumping out.

Important principles of a septic tank with a high groundwater level

In order to make a private sewage system with your own hands for a summer residence or a country house with a high GWL, you need to strictly follow several important principles:

Firstly, only plastic, and preferably fiberglass, should be used as a material for the cleaning structure. Its compressive strength is much higher than that of other types of PVC material. Moreover, the plasticity of such a container is also better. It is better to forget about septic tanks made of concrete rings or bricks right away. These materials have joints and are very hygroscopic, and therefore, with an increased attack of water from both sides, they will soon give up their positions. Even if at the installation stage you make a special coating with waterproofing mastic. And it will be too difficult to install a septic tank made of concrete, and even more so a brick on watery soil.

Important: the tightness of the septic tank chambers in the case of high GWL is first of all! Therefore, the choice of material for the storage tank must be well thought out.

The ideal option would be a septic tank specially designed and created by modern manufacturers. The design of such inventions has two or three chambers interconnected by overflow tubes. A completely finished plastic septic tank only needs to be installed in the ground, and you can operate it after connecting the sewer pipe. Such a septic tank works very efficiently, accumulating wastewater from all over the house, defending it and completely purifying it. As a result, there will be only clean water in the third chamber of the treatment system, which will remain to be pumped out.

Important: if your site is close to a reservoir, then you can save on the services of an assinizer and simply dump water into it. According to SNiP, household wastewater that has been treated through an industrial septic tank is considered 98% clean. And provided that aerobic bacteria are used in the septic tank, it is possible to reduce the amount of residual sludge in the chambers, and later use it as fertilizer for the garden or vegetable garden. Thus, having made the right choice, you will again be able to save on assimilation equipment.

It is worth remembering that a reliable sealed septic tank for an area with a high groundwater level needs mandatory cleaning as it is filled. Otherwise, waste water overflow may occur. So you should not neglect the pumping of wastewater.

If the option of a ready-made septic tank is not suitable

If you decide to save money and build a septic tank with your own hands, then here you will have to use either a monolithic concrete fill or ready-made plastic cubes. Let's consider both options of the device.

Septic tank made of PVC cubes... For a high-quality installation of the chambers, it is necessary to prepare a pit, which should exceed the parameters of the cubes by 20-30 cm. The bottom of the pit is well compacted and a layer of sand 30 cm thick is poured into it. A concrete slab is placed on the sand, which will become a reliable anchor for plastic. With the help of anchors and chains, the septic tank is reliably anchored.

After that, it is necessary to make a cement-sand sprinkling of the containers. The chamber of the septic tank is filled with liquid to 30 cm and sprinkling begins from the outside to the same height. Continuing to fill the chamber with water in stages and the distance between the septic tank and the walls of the pit, they move to the top. This technology makes it possible to insure treatment tanks against soil pressure and subsequent deformation.

After all the cubes are mounted, it is necessary to provide their overflow part with pipes. In this case, be sure to take care of sealing all joints. Lastly, the septic tank is covered with a stove to securely fix it. A ventilation pipe is brought out and provided access to the hatches, as indicated in the video below.

Monolithic concrete septic tank

For the device of a private sewage system in a swampy area, you can also make a monolithic septic tank made of concrete with your own hands. This choice is correct: the structure has no joints, which means it will be a reliable reservoir for domestic wastewater.

So, first we dig a foundation pit. We strengthen its walls with formwork and at the same time form a shape for the concrete pouring to the size of the pit. Immediately it is worth making all the partitions with pipes for overflow into them.
A reinforcing mesh is installed in the center of the formwork and along its entire height. It will make the concrete stronger after drying.
The mortar, reinforced with a hydrophobic additive for resistance to moisture, is poured into the formwork and left for 2-3 days. Under good weather conditions, the solution will set during this time. And it will take 7 to 10 days to completely dry.

Important: in the process of pouring the solution for its high-quality compaction, it is better to use a construction vibrator. So the finished monolithic septic tank will be practically non-porous.

After the tank has dried, it is advisable to coat it with a sealant from the inside.
The next step is to fill the bottom. First, the bottom of all three chambers is well rammed. After that, a layer of sand is poured, which is also carefully tamped.
A reinforcing mesh is laid on the sand and a solution is poured. They are waiting for it to dry completely.
Last but not least, a concrete floor is made. For this, the walls of the septic tank are covered with metal corners - stiffening ribs. Planks are laid on top perpendicular to the width of the chamber. If it is more than 1.5 m, then you will have to install the support pillars from below. Otherwise, the finished concrete fill will simply push the walls of the septic tank with its weight.
A mesh for reinforcement is laid on the boards, formwork is placed and mortar is poured. Do not forget about hatches and holes for the ventilation pipe.

It remains to connect the sewer pipe to the septic tank and start operating it, as shown in the video below.

If your site in a swampy area is used as a summer residence for seasonal visits, then here you can simply mount a storage tank in which wastewater will be collected. Over time, they will have to be pumped out using a sewer.

Another solution option may be to choose a special drainage fecal pump that can raise the effluent to a higher level and send it to a storage device located on the surface without burying it in the ground. But this version of a do-it-yourself sewer device is also optimal only for a temporary or seasonal dacha.

Arrangement of sewerage and treatment facilities in a summer cottage or a 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 a private house or cottage is located. If they go deep, then everything is fine, one less problem. But not all sites are in such favorable conditions - in some, the GWL 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 level of groundwater has its own characteristics and differences. And every owner of a summer house or cottage should know about this.

The problem of high groundwater for sewerage

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

Flooding- due to the heaving of the soil and the movement of groundwater, there is always a risk of moisture penetration 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 reservoirs quickly overflow with liquid, and it becomes necessary to call the sewer truck. And in the worst cases, streams of groundwater mixed with fecal masses from the septic tank will flow into the sewer, and then into the house, flooding the bathtub and toilet.
Surfacing- 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 put pressure on, 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 on the concrete pad, then they will begin to float upward. Often this phenomenon is accompanied by a roll, leakage and sewerage breakthroughs. As a result, a deteriorated cleaning system, flooding of a part of the site and the penetration of fecal matter into groundwater.
Drainage- one of the most important stages of sewage treatment is ground treatment. Water, passing through the septic tanks, enters special filtration fields. There, it seeps through the gravel bed and enters the soil, where it undergoes the last and most important stage of cleaning. According to sanitary standards, between the groundwater level and the filtration field, there must be a layer of earth with a thickness of at least a meter. Accordingly, it is quite problematic to fulfill this requirement with groundwater lying at 0.5-1 m. Failure to comply with these regulations will result in pollution of surrounding ponds, rivers and wells.
Waterlogging- the soil in the zone with high GWL is characterized by high humidity. Consequently, the ability to absorb post-treatment water will be worse. And if this factor is not taken into account, then the land around the septic tank will turn into a small swamp.
Septic tank damage- groundwater is often characterized by high alkalinity or, conversely, acidity. In such cases, they not only put pressure on the walls of the tanks and penetrate in the event of a leak, 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 communication pipes.
Installation problems- one of the main problems for the arrangement of treatment facilities in an area with a high GWL. When digging a trench, builders will have 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 seepage into the ground, mentioned several times above, is that the groundwater is constantly moving and mixing. And if somewhere fecal masses, sewage and harmful microorganisms got into them, then they spread over a large area. As a result, soil and groundwater are polluted, and nearby wells, streams and ponds are poisoned and undrinkable. In fact, a local ecological disaster occurs, which is caused by errors in other treatment systems.

Determine the depth of groundwater

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

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

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

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

Table. Plants are indicators that indicate the level of groundwater in the area.

Approximate groundwater level, m	Indicator plants
0 to 0.5	Sedge, cattail, reed, Langsdorf reed grass, marsh wild rosemary, downy birch
0.5 to 1	Canary grass, meadowsweet, cattail, reed,
1 to 1.5	Sand reeds, spruce, heather, blackberries, mouse peas, white bent, meadow ranch and fescue
From 1.5 and deeper	Alfalfa yellow, naked licorice, chiy, meadow clover, awnless fire, plantain, creeping wheatgrass, juniper, moss, lingonberry

The third method is the most accurate, but at the same time the most laborious. Let's represent 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 deeper drilling depth.

Step 2. Determine several locations in the area for the wells. It is desirable 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. For reliability, close the wells from above with waterproof material so that the night rain does not interfere with the determination of the GWL.

Step 5. Prepare a metal rod or wooden stick for the depth of the hole. Make a mark on the bottom of it every 10 cm.

Step 6. Immerse this "indicator" in the well and pull it out. Determine how wet the pin was and determine the GWL. As an example: a hole was dug 2 m deep, the pin was 30 cm wet.Perform the simplest calculations 200 – 30 = 170 , therefore, the groundwater level in this place is 1.7 m.

Step 7. Wipe off the "indicator" or let it dry and repeat the experiment with other wells in the area.

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

Important! It is best to take measurements in the spring, after the snow melts, when the groundwater rises to its maximum. If it's too long to wait until March or April, try experimenting in the summer or fall after a few days with heavy rainfall.

What should be a septic tank for a high level of groundwater

Consider the basic requirements that everyone must meet when placed on a site with a high level of groundwater.

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

Monolithic concrete septic tank - instructions

One of the most common designs, created independently for a country house or cottage. The walls and bottom of the septic tank tanks are reinforced with a grating and have sufficient strength so as not to collapse under the pressure of groundwater and earth from the outside. Due to its heavy weight, it cannot emerge in the spring or in the rainy season. In this case, we will consider step-by-step instructions for creating a three-chamber monolithic concrete septic tank that provides a significant degree of sewage treatment.

Step 1. Determine the place under), its dimensions, then start digging the foundation 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 already on the first day. Cover the walls with plastic wrap to prevent shedding. Tamp the bottom of the pit.

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

Step 2. Lay a tamped and moistened sand pillow 15-25 cm deep on the bottom.

Step 3. Proceed with the construction of the external formwork. In this case, use sufficiently thick and strong boards, since a large mass of concrete will be poured. If the formwork is too weak, he can simply spread it to the sides, especially in the lower part of a monolithic septic tank. Don't forget about the bar spacers.

Step 4. Begin to shape the reinforcement grid on the bottom and sides of the pit. Use steel rods with a cross section of 10 mm, wire them together. The side of each individual cell of the lattice is from 20 to 30 cm.

Step 5. Form a reinforcing grid on the partitions that 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 leak ground water and is not subject to destruction due to aggressive internal and external environment.

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

Step 8. Begin filling the outer walls and partitions of the septic tank. Don't forget to shape camera-to-camera overflow holes. When pouring, try to reduce the number of cold joints, as these will be the weak points in the structure, in which the leakage will occur first.

Step 9. Construct the septic tank roof formwork. In this case, the boards must be carefully fitted to each other. Do not forget about hatches and ventilation - each septic tank should have its own hatch for inspection, maintenance and, if necessary, disposal.

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

Step 11. Separately form a reinforced grating around the hatches and grout them.

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

The three-chamber monolithic concrete septic tank is ready. Next, you just have to make a branch from it to an embankment with a filtration field (for additional treatment of industrial water) or to a gutter.

According to a similar principle, a two- or three-chamber septic tank from eurocubes is equipped. In this case, it is necessary to take into account the high level of groundwater and, accordingly, the danger of surfacing. Therefore, plastic eurocubes are mounted on an anchor concrete slab previously poured or laid in a pit. It also makes sense to protect the structure with something from the sides from squeezing when the soil heaving.

When using a septic tank of industrial production, such as or, the same recommendations are valid - a concrete slab is installed at the bottom of the pit under the treatment plant, the tank itself is fixed on it using anchor belts, as in the image below.

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

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The use of a septic tank in a suburban area is one of the best solutions for the disposal of sewage waste. However, to create an optimal system, it is necessary to take into account many parameters and features of the site. It should be remembered that when choosing a septic tank with a high level of groundwater at the site, not every option is suitable. The level of purification, the method of discharge of processed water, the ability of the soil to transmit moisture far - is not a complete list of parameters that are of great importance. And yet, the main indicator that determines the efficiency of the wastewater treatment system should not be considered the productivity per day, not the percentage of treatment. The main criterion, perhaps, will be how clean the environment remains. After all, not only comfortable living depends on this, but also the health of the owners, their guests and closest neighbors.

It is recommended to measure the groundwater level during periods when it is highest. In spring - during the period of the most active floods associated with melting snow. In autumn, groundwater can reach its maximum levels after prolonged rains. The water table is the distance from the surface of the water table to the surface of the soil. If there is a well on the site, you can take measurements immediately without additional preparations. If there is no well, you should use a garden drill to make a hole in the soil and wait until it is filled with water. At the same time, it is advisable to make several holes in different places - this will allow obtaining the most objective measurement results.

Typical problems associated with high soil moisture and the proximity of groundwater:

The question of how to make a septic tank if the groundwater is close is very common. This issue is connected, first of all, with the risks of groundwater pollution. Most septic tanks involve the discharge of processed masses into the ground. Even with a serious level of purification of 98-99%, the industrial water obtained at the outlet of the septic tank is not suitable for drinking and poses a health risk if it gets into the water supply system. Waste water is used only for technical purposes - for household work, for watering trees, etc.

In the event that disposal on site is not foreseen, a conventional storage septic tank with a high carbon content must still be installed with certain safety measures. The risk of waste from the septic tank getting into the ground or a nearby reservoir can be due to various circumstances: seasonal floods, leakage of the storage tank, overflow of the container, malfunction of the control elements of the septic tank (if any) and the sewer line entering the septic tank.

Features of the placement of septic tanks

Septic tanks are most often buried in the ground. This has both practical and aesthetic purposes. However, with all the obvious advantages, placing a septic tank underground also has some disadvantages. Before starting work, you should learn how to bury a septic tank if the groundwater is close - even if it is an ordinary reservoir, there are risks. To exclude them, all work must be done correctly. Violation of the tightness of a septic tank, if it is located underground, is difficult to identify.

If placed incorrectly, for example, in a place that is lowered relative to the relief of the site, the septic tank is susceptible to flooding due to the accumulation of sedimentary or flood waters around the cover.

Flooding can also be caused by rising groundwater levels.

Due to flooding, the septic tank is filled, and water mixed with sewage can flood the site. In case of flooding, if the septic tank is made of plastic, there is a risk of the septic tank rising - to prevent this, a concrete slab is placed on the bottom of the pit in which the septic tank is placed, and the septic tank is attached to it.

Even when using a conventional storage tank, it is important to take into account the nearby groundwater - a septic tank that does not involve waste processing is installed in compliance with the norms and standards provided by law. There is always the possibility of an emergency. A septic tank in the form of an ordinary container assumes the removal of waste when the container is filled with a sewage machine. During installation, it is necessary to ensure the possibility of free vehicle access to the septic tank. It should also be borne in mind that the procedure for pumping sewage is not the cleanest process, so the location of the septic tank on your site should be chosen deliberately.

The importance of eels depending on the type of septic tank

Septic tanks that process waste, in most cases, imply the removal of the processed mass into the soil. They can be of two types - a septic tank with an overflow and a single-container septic tank.

An overflow septic tank, as a rule, consists of several wells isolated from the ground and interconnected. Sometimes a monolithic concrete septic tank is made with internal partitions dividing the entire container into separate compartments. The number of wells or compartments can be different, usually there are two or three. The last tank in the overflow septic tank is a filter well for a septic tank - treated wastewater seeps into the soil through the bottom covered with sand and gravel. Drainage into the soil implies two functions at once - additional cleaning and
recycling. The level of purification in such septic tanks is often not too high. A high groundwater level, in this case, makes the drainage into the ground unacceptable. Nevertheless, using a concrete septic tank with a high level of groundwater, in certain conditions, the solution is to use an aeration field instead of a drainage well.

The use of a waste bioprocessing station that provides a level of purification of 98-99%, for example, a septic tank Topas from vega, does not allow the direct ingress of water formed after processing into the well, although the criticality of entering a nearby reservoir decreases, especially if the water is running there. This water is suitable for irrigation.

Soil characteristics taken into account in the calculations

When calculating the parameters of the purchased septic tank, one should take into account the characteristics of the soil into which the septic tank will drain the processed wastewater. The omission of any factor can subsequently lead to the inoperability of the entire
systems.

The main soil parameters that should be taken into account when choosing a disposal system:

Soil type.
The ability of the soil to pass water.
The depth of soil freezing.

Some types of septic tanks are initially targeted for use in sandy soil. As a rule, such installations are characterized by a low level of purification and imply a relative remoteness of groundwater at the place of use. The sand provides high throughput. Also, in sandy soil, the likelihood of poorly processed waste does not cause siltation so quickly. It is impossible to use such a septic tank for clay soil, since clay has a low throughput. Runoff can reach the surface of the relief and flood the site. If the only possible option is to drain water from the septic tank with clay soil, then the use of additional measures is inevitable.

In addition to making global improvements to the entire system, you can take advantage of an inexpensive and effective solution by installing a septic tank filter at the outlet of the system, thereby reducing the risk of soil siltation. It is advisable to use such a filter both for soil with low flow capacity and for septic tanks that drain wastewater using aeration fields. The filter retains particles remaining in the water, and thereby significantly reduces the intensity of soil siltation. In the case of using filter fields, the filter helps to avoid fast clogging of drainage pipes.

If the site is characterized by large volumes of wastewater, and the septic tank is used all year round, the use of the same filtration fields is limited at low temperatures. Freezing leads to serious environmental pollution. High soil moisture also imposes certain restrictions on wastewater disposal.

What if the drainage efficiency becomes low?

The likelihood of siltation of the soil into which the treated waste is discharged is inevitable. The owner's task is only to build a high-quality system in order to postpone this moment as much as possible. If the water does not leave the septic tank, what should be done to effectively solve the problem? It is necessary to carefully analyze the operation of the entire system. The nature of the problem can be caused both by the period of use of the septic tank or by an emergency, or by an initially incorrect installation of the entire system. If the septic tank is used for a short time, it is very likely that the malfunction is caused by mistakes made during installation.

If the septic tank has been used for more than a year, it is very likely that the drainage will become silted.

If the filter well is clogged, then the well must be emptied and the bottom must be cleaned with sand and crushed stone. If the pit is full, it is necessary to call a sewage truck to pump out the sewage. On your own, you can carry out pumping using a special pump. In the case of filtration fields, the situation is somewhat more complicated. Drainage pipes may need to be cleaned - if stagnation is caused by contamination. Silting up the soil may require digging up or replacing its top layer.

Groundwater level is one of the most important aspects when equipping a site with a septic tank. A high GWL forces either not to dump waste into the soil, or to provide a very high level of purity of the discharged water. In addition to GWL, there are many more parameters that can affect the quality of the system. Only after calculations can we confidently say for clay soil, which for sandy, taking into account also the throughput of the soil, the proximity of water bodies and the depth of freezing.

However, choosing the best septic tank for your site does not always mean buying the most expensive model. In cases where the volume of wastewater is small, there are few users, or the use of a sewage system is of a seasonal nature, it is quite possible to buy a septic tank cheap with the simplest configuration. And this will be the best solution for a specific site.

If you are not confident in your own abilities, you need to contact the specialists of the manufacturer. For example, the masters of the Unilos company install turnkey septic tanks Astra 5, and if the manufacturer carries out the installation, he takes into account all the technical features of the system and the probability of error is minimal.