Septic tank high ground water. Septic tanks for cottages with a high level of groundwater. Septic tanks with forced

Self-arrangement of communications is an economical right decision. Sewerage at a high level of groundwater has the nuances of construction and operation. The peculiarity of the cesspool for such a house as a private one is its tightness.
The construction of sewers for high groundwater is quite expensive, but this way you are guaranteed to see a quality result. How to make a sewer so that it meets all the requirements of sanitary safety and serves for many years? Consider the proximity of moisture to the soil.

Risks of proximity to groundwater

Groundwater is an underground aquifer that is close to the surface of the earth. The groundwater level is able to rise up if heavy rains or snow melts the day before. In dry weather, the amount of subsoil moisture decreases.
The elevated soil water level complicates the arrangement of treatment systems, wells and the foundation of buildings:

• the structure of the street toilet is destroyed.
• an unpleasant odor appears;
• increased risk of intestinal infections;
• the service life of underground pipes is reduced - metal corrosion occurs.
• water erodes the walls of the cesspool, which prevents its purification.

There are several ways to understand how close groundwater is:

1. Liquid level measurement. In the spring, you need to measure the water level in the well. A visual assessment is carried out by checking the filling of the tank after heavy rains or snowmelt.
2. In the absence of a well, you can drill several holes with a garden drill and see if they fill with water.

If both technologies are not available to you, contact your neighbors who use local treatment facilities.

Construction of a cesspool

The construction of a sewerage system in a private house with a high level of groundwater in the form of a cesspool is undesirable. Possible flooding threatens with the complexity of cleaning, rapid filling, erosion of the edges of the trench and destruction.

Storage capacity: installation features

The design is an ordinary pit, barrel or well made of concrete rings. The advantage of structures is their low cost during construction. There are quite a few cons:

• the container should never overflow, so choose products with a large capacity;
• with a high GWL, the tank must be regularly treated with sealants;
• place the structure in a place convenient for the entrance of the sewage service;
• the frequent call of a sewage truck means financial costs for the owners.

The storage tank is budgetary in construction, but its operation can take a lot of time and money.

Installation of a mechanical septic tank

Country sewerage with a high level of groundwater should be leak-tight. A mechanical septic tank is popular due to its price-quality ratio. The large outlays at the initial stage are paid off by the simplicity and reliability of the system operation.

The degree of purification of waste liquids is regulated by adding wells.

With a low level of soil water, 1 will be enough, with a high level - 2 or 3 wells. The choice of materials for the construction of a septic tank must be approached responsibly, since with high groundwater it is necessary to prevent flooding of communications. Wells can be plastic or concrete, but the criteria for their organization are the same:

• when installing a septic tank from ready-made concrete rings, all joints must be carefully processed. This will prevent the destruction of the structure;
• the ideal option is to cast the well on site. To do this, you need a form of iron, which can be rented;
• plastic septic tanks, when properly installed, will be durable and effective.

The dimensions of an autonomous sewer for a private house must be calculated correctly. Its capacity is equal to the amount of water consumed by a family of 4 people in 3 days.

The advantages of a septic tank with a close location of groundwater

Installing a sewerage system in the form of a septic tank in a private house with a high level of groundwater has many advantages:

• absence of an unpleasant smell thanks to tightness of a design and ventilation.
• there is no need to call the cesspool service. Waste decomposes and is discharged into the deep layers of the soil.
• there is no risk of contamination of the soil with waste. Waste liquids undergo thorough multi-level filtration. However, it is not recommended to install a sewer in the vicinity of drinking wells.

With proper operation, the structure will maintain durability and integrity.

The principle of operation of autonomous sewage

Autonomous country sewerage, properly constructed at a high level of groundwater, can improve the quality of life of site owners. The multilevel system works according to the following principle:

• the used liquid flows into the septic tank, where insoluble inclusions are retained.
• solid particles settle at the bottom of the container, while fats and insoluble substances form a film on the surface.
• wastewater enters the septic tank, where it is treated with anaerobic bacteria.
• the organic environment that comes with the wastewater promotes the growth of bacteria that reduce the concentration of harmful substances.
• ventilation removes the gases formed during the decomposition process.

The settled and clarified liquid enters the infiltration tunnels, where it is cleaned and discharged into the ground.

Septic installation algorithm

Making a sewer in a private household is not difficult if you follow the correct procedure.

Regulatory regulation of the sewerage device

Home cleaning system requires careful observance of sanitary rules. The removal of sewage from the house, as indicated in the requirements of SNiP 2.04.03-85, provides for:

• placement of treatment facilities 50 meters from drinking wells or wells.
• sewer communications are located 3 meters from the plantations.
• the septic system is installed at a distance of 5 meters from residential buildings.
• sewage equipment must have unhindered access to the treatment plant.

Planning of cleaning networks is carried out in a strict order - 1 revision well for 15 m of straight or turning sections. Work must be carried out in a strict order.

Digging a pit

Conducting home sewerage for a summer residence, if groundwater is close, it starts with digging a hole:

• the septic structure is fully included in the pit. In this case, the tank should not touch the walls at a distance of 25 cm;
• observe the maximum evenness of the bottom, compacting it with wet river sand. Fine-grained material is laid in a layer of about 15 cm and carefully compacted. The sand should not contain foreign particles in the form of lumps of earth or gravel.
• to ensure the tightness of communications, the sand is replaced with a concrete slab.

The walls of the pit must be reinforced with timber formwork or metal sheets.

Installing a septic tank in a pit

The finished septic tank is checked for cracks and damage before installation.

The container is lowered to the pit with the help of cables. It should stand perfectly even in the pit, even the slightest roll is unacceptable. In cold winters, it is recommended to wrap the tank with a layer of heat-insulating material.

Trench backfill

After installation, the tank is covered with soil or cement-sand mixture and carefully compacted. The ground level reaches the edge of the supply pipe.

Arrangement of the infiltrator

Filtration facilities must be connected to the tank to purify water before it enters the ground from the tank. There are several options:

• Filtration fields with a bed of gravel and sand, where perforated drainage pipes are located along an inclined line. The length of the pipes reaches 20 meters, and the distance of the extreme points is 2 meters. Filtration is located 1 meter higher than the proposed elevated aquifer.
• Water supply to the ditch is suitable for clay soils. The filtered water is removed by pumps.
• A water intake for a house, like a filter, is built when water is planned to be used for agricultural needs, or it is not possible to build another structure. Pipes are connected to the tank from the septic tank. A sand cushion is necessarily built around. To protect against overflow, an outlet pipe is constructed, which, with a large amount of water, leads it into an underground filtration field, a ditch or back into the septic tank.
• A good solution for a private house, under which there is a high level of groundwater, is a ground filter cassette. It is built as follows:
  • dig a hole 50 cm deep, which is filled to the top with sand.
  • foam blocks about 30 cm high are laid around the perimeter.
  • crushed stone is poured inside.
  • a filter cassette made of plastic and insulation is placed on top.

Your sewer septic tank will begin to function normally only after 2-3 weeks have elapsed. During this period, a sediment of sludge is formed at the bottom of the tank, which is actively involved in the process of waste processing.
The quality of the sewerage made in the country with their own hands directly depends on the quality of the containers and pipes used, as well as the correct installation.

Proper construction at a high level of groundwater of the country sewerage system will ensure the filtration of sewage liquids by 99%.

However, the resulting water is not edible and is purely technical.

The close occurrence of groundwater is a factor that greatly complicates the installation of a septic tank on the territory of private country estates. Therefore, when planning the construction of engineering communications for a summer house or a house, it is necessary to take into account the "situation" on the ground. Ground water at the level of up to a meter is definitely a problem. A septic tank for high groundwater must be equipped in accordance with all the rules - otherwise the operation of the structure will be a complete headache.

How to determine the level of groundwater?

It is recommended to measure the groundwater level in spring, when the snow melts, or in autumn after prolonged rains. The distance between the surface of the earth and the “water surface” in the well, “feeding” on groundwater, is subject to measurement. No well? You can also determine the level of groundwater by drilling the soil with a garden drill in several places (for objectivity of observations). Well, the easiest method is to just talk to your neighbors and find out from them how things are in the area.

A high level of groundwater can be a problem when arranging a septic tank - but knowing the rules for carrying out work, many typical mistakes are easy to avoid

The problem of high GWL is typical for almost the entire territory of central Russia. Groundwater flows can occur even at a depth of 20-30 cm.

What is the insidiousness of the swampy area?

When arranging and during the operation of an autonomous sewage system in a site with a high level of groundwater, each homeowner may encounter such problems:

1. The complexity of installation. What sweet speeches you would not have heard from sellers of different types of structures, do not believe it - it will take a lot of time and effort to install a septic tank. However, having worked "at full capacity", there will be no doubt that the sewage system with a septic tank will serve you faithfully, perhaps even for more than a dozen years.
2. The emergence of a septic tank. If the septic tank is not installed on a concrete pad and secured with straps, nylon ropes or cables, there is a high probability that groundwater flows will provoke the septic tank to rise. As a result, the integrity of the structure of not only the septic tank itself, but also the entire sewer pipeline, has been violated.
3. In a leaky septic tank, made, for example, of concrete rings, water will constantly leak. And this means that you will have to resort to the services of a sewage machine very often. Needless to say, it is very expensive?
4. Complete flooding of the septic tank. The systematic flow of liquid into the septic tank will quickly render the structure unusable.
5. Sewage seeping into the soil can become a source of groundwater pollution. Where it leads? It will take quite a bit of time and the water from the well will become unusable. Ponds adjacent to the site are at risk of blooming. There will be a local ecological catastrophe.

A septic tank installed on a site with a high level of groundwater must be completely sealed - otherwise you risk both your health and the contents of your wallet

Basic device rules for high GWL

The septic tank, if groundwater is close, must be completely sealed in order to prevent seepage of runoff into the soil. Structures, bricks and other prefabricated elements are not able to provide proper tightness - therefore, such options should disappear even at the stage of theoretical reflections on the sewage system. Ideally, it is desirable to resort to installing a septic tank of industrial production. On the market there is a wide range of these devices with different volumes. It is worth knowing that the volume of the septic tank should be equal to the three-day volume of water consumption by people living in the house.

Having studied, you will see that today you can easily purchase both a compact design for a small cottage and a multi-chamber installation designed for a modern cottage.

A three-chamber factory septic tank is a plastic container divided into chambers. The first chamber is a place for settling and dividing wastewater into fractions. The second and third are intended for post-treatment of wastewater. Instead of filtering wells, infiltrators are used in such structures - they provide rapid absorption into the soil of 94-98% of purified water. The main disadvantage of infiltrators is their large area. The industrial septic tank itself is, of course, quite expensive. However, such an investment is by no means an excess or a whim. A quality septic tank with high groundwater is a vital necessity.

With limited funds, you can build a septic tank yourself - from suitable plastic containers, for example, and design. Between themselves, the containers must be connected with special pipes for the flow of wastewater.

If industrial solutions do not suit you for one reason or another, you can always build a septic tank with your own hands

When equipping a septic tank in an area with a high GWL, it is necessary to provide a reinforced concrete pillow under the structure. By attaching the structure to such a base, it will be possible not to worry that it will be pushed out of the soil.

Also a good option for installing a septic tank with a high level of groundwater is the installation. Due to the absence of seams, the penetration of effluents into the ground will be impossible. The order of work will be as follows:

• digging a pit;
• formwork installation;
• fittings installation;
• pouring concrete.

It is advisable to pre-flavor the concrete mixture with a hydrophobic additive - this will improve the waterproofing properties of the future structure. Overflow holes must be provided in the partitions between the chambers. Inside, the finished chambers must be treated with coating waterproofing. If desired, such a septic tank can be built independently, without the involvement of specialists. It is enough to plan your work correctly and take into account all the nuances.

What other solutions are there to the problem?

If you have a small dacha that you visit two or three times a month, then the easiest and most cost-effective option for you would be to install a storage tank. It is desirable that it be made of fiberglass by machine winding. How would such a design work in practice? Drainage from housing will gradually accumulate in a sealed container, and then “extracted” by a sewage machine. For rare visits, a three-cube storage tank is more than enough for a whole season.

One of the most important components of the competent use of a septic tank is its high-quality, timely, professional cleaning - therefore, the services of a cesspool machine should by no means be neglected!

As you can see, you can arrange a septic tank with a high GWL in many different ways. It is impossible to say which of them will be optimal for you in absentia. It all depends on your financial capabilities, the type of housing (permanent or temporary), the specific conditions of the area. After consulting with a competent specialist, we are sure that you will be able to make the right decision.

Hello, friends.

I want to touch on such a burning topic, I’m not afraid of this word, like self-made concrete at a high groundwater level.

Of course, we all want to save money and not buy Topas and Yubasa for crazy money. But at the same time, we want the blood bablos buried in the ground not to go to waste, that is, to work, purify, and not spread aromas.

There are a number of problems with concrete septic tanks with a high GWL:

1. It is difficult to concrete the bottom, often people do not bother with this, and bury the first well without a bottom. Then, for some reason, they still make a drain from this well in the filtration field, although a well without a bottom is already a filtration well in itself.
2. Difficult to seal rings. It is not so much important here that the concrete will let wastewater out, passing through the concrete they will be cleaned better than even reaching the last well. Worse, groundwater can get inside and change the level of liquids in the chambers. For example, if the water in the second chamber rises above the overflow with the first chamber, then the liquid in the two chambers will mix and will be of the same degree of purity. The same with the third chamber, and it turns out a single-chamber septic tank with a large chamber of a cunning shape. The degree of purification is zero.
3. And most importantly, for soil filtration, you cannot make a 3rd well. You need to make an embankment, for the same reason. So that the water does not go back into the septic tank, and does not make senseless the presence of 3 sump chambers, mixing everything together, as well as blocking the ventilation holes, and making the septic tank smell fragrant. So an extra pile on the site is inevitable.

Save for Topas? In no case!

You can save money by making two sealed chambers, and pouring into the third one through the pump and check valves!

But, in order.

1. To begin with, I would not use rings, but would fill everything myself. I would pour a monolith, in my opinion, it is easier to seal it, now there are a lot of additives and means for waterproofing concrete, and there will be no problems with the displacement of the rings. Again, it is easier to dig a hole, and most importantly, you can avoid flooding the hole with groundwater.
To do this, an auxiliary, small pit is dug next to the main pit, the pits must be communicated. The small hole should be deeper. The bottom of the main pit should be sloping towards the small one, rubble should be poured onto the bottom of the main pit so that all the water flows over the rubble into the small pit. And in this smallest hole we throw a pump for dirty water, which turns on the float, and that's it, you can fill it. Now the main pit will always be dry.

2. We put the formwork, fill in two sealed chambers, and one without a bottom. Between the first two chambers, the communication will be absolutely standard, pipes, tees ... But between the second and third chambers, we cut a check valve into the wall. There is no particular hope for gravity flow, so we hang a pump with a float from a small pit in the second chamber (non-waste production), so that it turns on at the moment when the liquid does not reach the overflow level between the first and second chambers 5 cm.

Thus, we get the first two chambers from the bottom, sealed, in which each chamber works normally in its function, thanks to the correct levels of liquids, and a filtration well, in which the water level does not affect the operation of the first two chambers, even if it is under the surface. Also, there are no heaps.

I want to start as soon as I go on vacation, i.e. from Saturday.

Well, do you think it will work out, or is it time to give up?

Installation of a septic tank at a high groundwater level (GWL) is a rather complicated, but possible procedure. Before starting construction work, it is important to find out the exact value of the GWL, for this you can use both professional and folk methods.

Based on this parameter and the required volume of the tank, models of septic tanks should be selected. It is best to install ready-made factory designs.

They are more expensive, but compare favorably with the service life and the need for less effort during installation.

How to accurately determine GWL

There are several ways to determine the level of groundwater. The most effective and simplest is to contact a special organization that conducts geological examinations.

As a result, the owner of the site will receive a detailed report on the groundwater level, on the basis of which it is possible to design subsequent construction work. However, this is a rather expensive procedure, so it is not suitable for everyone. There are other methods for self-determining the level. These include the following methods:

1. through a drilling rig;
2. by flora;
3. by nearby water sources;
4. old folk technique;
5. by omens.

For the first method, you will need a garden drill and a rod with a length of more than 2 meters. On the rod, mark under the tape measure with a 10-centimeter interval. Then you will need to dig a hole to the maximum length of the drilling tool.

Sometimes water comes through immediately when drilling, but most often you need to wait a day for it to appear there. The rod is lowered to the entire length of the well, and then it is removed and the level to which the water has reached is checked.

This procedure must be repeated several more times, fixing the marks obtained. If the results differ, then you need to take the minimum option. For the objectivity of the check, it is desirable to carry out the procedure in autumn or early spring, when the depth of groundwater is minimal.

You can also recognize the GWL by the vegetation that develops in the area without additional irrigation. In the image below you can find the most common plants.

The free growth of sorrel and currant bushes can also testify to the close location of water. By the angle of inclination of birch, maple and willow, you can find the place of the minimum depth of groundwater.

Quite often, there are water sources in the nearest area: wells (even small ones dug for irrigation), reservoirs, etc. According to their depth, you can also come to the desired conclusion. Also, the presence of swampy reservoirs testifies to the high level of groundwater.

You can always find out about the waters from the owners of neighboring plots, it is likely that they carried out an examination when building houses, building septic tanks or connecting to a central sewer.

There is also a folk method: remove the top layer of soil from a small area, put defatted wool, and a fresh egg on top of it. Then this composition is covered with ceramic dishes and left untouched during the night.

Then they remove it and check the items. If the wool is a little wet, and there are no drops on the egg, the level is low. If there are drops on the egg, then the GWL is high. However, this method will not help you find out the exact value.

An abundance of midges, mosquitoes and other insects may indicate increased soil moisture; the minimum number of rodents and anthills; love of cats to such places; the presence of fog and dew in the morning even in hot weather.

Problems arising from high GWL

With such a feature, the owner of the site will face difficulties:

• the complexity of installing a septic tank with a high level of groundwater. Despite the frequent assurances of sellers, this procedure will require a large amount of time and resources;
• it is necessary to immediately design a septic tank with drainage, otherwise the nearby area will turn into a swamp;
• the possibility that the sewer system will be completely flooded, because. new water continuously flows;
• it is necessary to pay attention to mounting the base and fixing the septic tank with cables or fastening straps. If this is not done, then the storage septic tank will rise at a high level of groundwater, as a result of which sewage will enter the site, and the integrity of the system will be violated;
• you will need to use special materials for the construction of sewers and ensure its tightness. For example, the use of concrete rings can cause liquid to enter through the walls;
• when runoff water enters the groundwater, they will quickly spread throughout the area. As a result of this, it will not be possible to use water from the well, and the nearest reservoirs will begin to bloom. Because for the accelerated decomposition of sewage, a large number of bacteria live in the septic tank; if they enter human food or water, they can lead to indigestion, as well as to various infections and diseases;
• when the septic tank overflows, drain liquids can go in the opposite direction, as a result of which the pipes will break. Along with liquids, fine sand and other elements will pass that can cause damage to the material of the pipeline and plumbing, which will require repair or replacement of appliances located in the house.

TOP 10 manufacturers of septic tanks for high GWL

According to customer reviews, we can distinguish the TOP of the best manufacturers of autonomous sewers with an increased level of groundwater:

1. The septic tank "Tank" is designed in such a way as to prevent the structure from floating. Designed for a large volume of liquid, copes well with temperature changes. Models are made of plastic, do not require external energy sources and have 17 mm walls.
2. "Leader". 6-chamber septic tanks with aeration and airlift. Do not require additional use of bioactive drugs.
3. "Leopard". There are models that require and do not require power. 3-chamber septic tanks with 2 levels of waste filtration. Differ in durability and a possibility of long operation.
4. "Yubas". The main difference between these models is that they can be used intermittently up to 3 months without reducing the efficiency of functioning. Ideal for suburban housing.
5. Ecopan. It is considered the best septic tank for installation with a high level of groundwater. Models are able to withstand heavy loads without loss of performance.
6. "Tver". They require an additional power supply and regular maintenance, but they have a large capacity and can handle large volumes well.
7. "Triton". Septic tanks must be anchored with nylon cables or chains. They have a long service life.
8. "Topas". These stand-alone models are known for their high reliability and durability. They are made from modern high-quality materials with increased wear resistance. In this article, you can more.
9. Unilos. Filtration and drainage of waste liquids in a septic tank is carried out in several stages. Models do not require complex maintenance and are completely safe for the ecological situation of the area.
10. "Poplar". They are resistant to temperature changes and external pressure. Septic tanks have aeration, compressors, airlifts. You can eliminate drains manually or with the help of special sewage equipment.

Choosing a place for a septic tank

To determine the optimal place for the construction of a septic tank, you should study the current rules and regulations. There are several conditions that must be taken into account:

• the septic tank must be at least 5 meters from the house or any building ();
• the road zone should be located at a distance of 5 meters;
• sewerage and aeration station should be located at a distance of 30 meters from an open reservoir or reservoir and 50 meters from a well with drinking water.

Which septic tank to choose for the site

The choice of a suitable model primarily depends on the required volume. As a rule, for an approximate calculation, the daily volume of liquid from the house, multiplied by three, is used. Most often, ready-made septic tanks are used for erection on a suburban area, or they are assembled directly during installation with independent provision of tightness.

Sometimes owners decide to install a surface sewer system independent of groundwater. However, this solution is associated with certain difficulties, because. you will need to install numerous pumps, and for such a septic tank you need a lot of space on the site.

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Despite the rather high cost of this type of system, the absence of the need for the services of vacuum trucks allows the price to pay off within a few years.

Another possible problem is soil heaving. This process involves an increase in the volume of the earth due to freezing, when the water in the soil becomes ice. The higher the GWL, the stronger this property manifests itself.

To prevent the negative effects of heaving, a mixture of sand (5) and cement (1) should be used. During the construction of a septic tank, with a high level of groundwater, a small space is left between the two walls (about 15-25 cm). In the resulting "pocket" it is required to fill in layers and tamp the mixture diluted with water.

When backfilling, water is poured in parallel so that both levels coincide. This action will protect the septic tank from cracks and other damage.

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However, sometimes it is not possible to postpone the construction for various reasons, so it is necessary to immediately solve the problem. To do this, most often the incoming liquid is scooped out in parallel with digging the pit.

As a rule, sewer equipment is used for this. You can also use a regular hose with a mechanical pump, but it must be of large diameter in order to pump out water with small stones, sand and other elements.

To simplify pumping, it is recommended to first dig a trench at the lowest point, then proceed to dig the rest of the area. This will lead to the fact that in the process all the water will be collected in one place, from which it can be easily pumped out with a pump.

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However, all of the above recommendations apply only to the manual creation of a pit. If this process is carried out using special equipment, then quick digging will not allow a large amount of liquid to enter the trench, therefore, this will not interfere with the construction work.

To ensure the stable and efficient functioning of a septic tank in a country house or in a private house with a high level of groundwater, you should follow some tips:

• large waste and durable garbage cannot be dumped into an autonomous sewer;
• the entire system must be qualitatively insulated and waterproofed;
• if there is no drainage, then it is required to independently pump out sewage liquids manually with a sewer pump or using the services of sewers;
• it is advisable to install grease traps on plumbing fixtures (especially in the kitchen), which will prevent grease from entering the septic tank. It is the formation of a fatty layer and silt on the walls and bottom that is the main reason for the rapid filling of the container;
• if there is a biological cleaning step, it is forbidden to use strong chemicals to clean plumbing fixtures. Also, alkalis, acidic substances, alcohol should not be allowed to enter the septic tank in other ways, because. they are able to destroy beneficial microorganisms that process sewage.

Watch the video

Installing a septic tank at a high GWL is a serious procedure that requires a lot of time. It is important to choose the right material and type of construction, determine how many chambers and what capacity is needed.

Before starting installation, it is necessary to accurately know the level of the depth of groundwater, this can be done using a drilling device or in another way.

A high-quality septic tank with a high GWL can work without problems for many decades.

The arrangement of sewage and treatment facilities in a summer cottage or personal plot requires taking into account many small things and nuances that at first glance seem insignificant. An example of such a factor is the groundwater level (or GWL for short) in the area where a private house or cottage is located. If they lie deep, then everything is fine, one less problem. But not all sites are in such favorable conditions - in some 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, differences. And every owner of a summer house or a cottage should know about it.

The problem of high groundwater for sewerage

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

1. Flooding- due to heaving of the soil and the movement of groundwater, 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 overflow with liquid, it becomes necessary to call a sewage truck. And in the worst cases, groundwater flows mixed with fecal masses will flow from the septic tank into the sewer, and then into the house, flooding the bath and toilet.

   

2. 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, they would start to float up. Often this phenomenon is accompanied by a roll, leakage and sewer breaks. As a result, a cleaning system that has become unusable, part of the site is flooded and fecal matter penetrates into groundwater.

   

3. Drainage- one of the most important stages of sewage treatment is soil post-treatment. Water, passing through the septic tanks, enters special filtration fields. There, it seeps through a bed of gravel into the soil, where it undergoes the last and most important stage of purification. According to sanitary standards, between the GWL and the filtration field there must be a layer of earth with a thickness of at least a meter. Accordingly, it is rather problematic to fulfill this requirement with groundwater lying at 0.5-1 m. Ignoring these norms leads to pollution of the surrounding ponds, rivers and wells.
4. swamping- the soil in the zone with high GWL is characterized by high humidity. Therefore, the ability to absorb water for post-treatment 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.

   

5. Septic tank damage- 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 in case of leaks, 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.

   

6. Installation problems- one of the main problems for the arrangement of treatment facilities in areas with high GWL. 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 seepage of sewage into the ground, mentioned several times above, is that groundwater is constantly moving and mixing. And if fecal masses, sewage and harmful microorganisms got into them somewhere, then they spread over a large area. As a result, soil and groundwater become polluted, and nearby wells, streams, and ponds become poisoned and undrinkable. In fact, a local environmental disaster occurs, which was caused by errors in other treatment systems.

Determine the depth of groundwater

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

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

• polling neighbors;
• search for indicator plants;
• drilling of exploratory 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 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. Indicator plants that indicate the level of groundwater in the area.

The third method is the most accurate, but at the same time the most time-consuming. We will present it in the form of a step-by-step instruction.

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 desirable that one of them is located where it is planned to install a septic tank and treatment systems.

Step 3 Drill a hole 2 m or more deep.

Step 4 Wait a day. For reliability, cover the wells from above with waterproof material so that night rain does not interfere with the determination of GWL.

Step 5 Prepare a metal pin or wooden stick under the depth of the well. Put marks on its lower part every 10 cm.

Step 6 Immerse this "indicator" in the well and pull it out. Determine how long the pin turned out to be wet and determine the GWL. As an example: a well was dug 2 m deep, the pin turned out to be 30 cm wet. Perform simple 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 more or less accurate results.

Important! It is best to take measurements in the spring, after the snow melts, when groundwater rises to a maximum. If March or April is too long to wait, experiment in summer or autumn after a few days of heavy rainfall.

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

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

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

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 tanks are reinforced with a grate and have sufficient strength so as not to collapse under the pressure of groundwater and earth from the outside. Due to heavy weight, it cannot emerge in the spring or in the rainy season. In this case, step-by-step instructions will be considered for creating a three-chamber monolithic concrete septic tank, which provides a significant degree of sewage treatment.

Step 1. Determine the place under), its dimensions, then proceed to dig the 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 shedding of the walls, lay them out with plastic wrap. Tamp the bottom of the pit.

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

Step 2 Lay a compacted and moistened sand cushion at the bottom with a depth of 15-25 cm.

Step 3 Proceed to the construction of the outer formwork. Use at the same time thick enough and strong boards, as 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 the monolithic septic tank. Do not forget about the spacers from the timber.

Step 4 Begin to form a reinforcing lattice at the bottom and walls of the pit. Use steel bars 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 lattice 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 leak groundwater and is not subject to destruction due to the aggressive internal and external environment.

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

Step 8 Proceed to pouring the outer walls and partitions of the septic tank. Don't forget about forming overflow holes from chamber to chamber. When pouring, try to reduce the number of cold joints, as they will be the weak points of the structure, in which 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. Do not forget about hatches and ventilation - each chamber of the septic tank should have its own hatch for inspection, maintenance and, if necessary, sewage.

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

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

Step 12 Inside, mount the tees of the overflow holes, fill the septic tank with soil on top, install the manhole covers and the ventilation system.

A three-chamber monolithic concrete septic tank is ready. Then you just have to make a diversion from it to an embankment with a filtration field (for post-treatment of technical water) or to a sewer.

According to a similar principle, a two- or three-chamber septic tank from European cubes is equipped. In this case, it is necessary to take into account the high level of groundwater and, accordingly, the risk of ascent. 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 from the sides with something from squeezing during heaving of the soil.

When using an industrial septic tank, 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 with anchor straps, as in the image below.

If you consider yourself not too well versed in construction and are in doubt, 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 improving a site, money is spent either at the construction stage or after it, but already on correcting mistakes and dealing with the consequences of savings at the expense of reliability.

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