How to preserve a septic tank for the winter: step-by-step instructions

A septic tank of a constantly functioning sewer system does not require conservation - its winter operation is no different from work in any other season. But a treatment plant in a country house, where people visit only from time to time, requires special attention.

If you do not take care of the structure, then by spring the house may lose its sewer system. Let's figure out how to preserve a septic tank for the winter, what rules should be followed, and what measures should be abandoned so as not to provoke a breakdown of the autonomous sewer system.

Why stop the operation of the country septic tank?

Preservation of a septic tank is the temporary suspension of its operation for the winter period with the possibility of starting it again when weather conditions are more suitable for this. It is necessary to maintain the functionality of the structure.

If the septic tank is used in winter for its intended purpose, everything will be fine with it, but for country sewerage, conservation measures are necessary. Otherwise, the septic tank body may be damaged.

This often ends with the appearance of internal and external leaks, partial or complete stoppage of the structure.

Measures to preserve a septic tank are much cheaper than subsequent repairs and restoration. All work can be done with your own hands

The purpose of conservation is to suspend the operation of the system so that it can be easily resumed.The system functions thanks to natural decomposition agents – anaerobic and aerobic bacteria. The speed and efficiency of sewage treatment depends on their type and quantity.

In conventional septic tanks, wastewater is purified by approximately 50-75%, and in biological treatment stations - by 95-98%. When preserving, it is necessary to create conditions in which microorganisms inhabiting different types of septic tanks, will remain alive and capable of reproduction.

This means that they must have nutrients, and aerobic bacteria must also receive oxygen.

If the septic tank is installed correctly (below the soil freezing level), you don’t have to worry that it will freeze. In addition, during their life activity, bacteria produce additional heat, and the temperature in the tanks usually does not fall below +5°C (+)

Some septic tank models use biological filters that improve the quality of wastewater treatment. They successfully replace filter fields, however, owners sometimes have to clean or replace systems and use special biological products.

In addition to the high cost of the structures themselves, it is necessary to constantly invest in their performance, take care of proper preparation for cold weather and septic tank maintenance in winter.

Completely pumping out the tank is a fatal mistake

A common mistake made by septic tank owners during conservation is pumping out the tanks. If there is no liquid left, the bacteria quickly die from lack of food. In this case, in the spring you may encounter big problems during the operation of the sewer system if measures are not taken in a timely manner to increase the number of microorganisms.

The treatment plant will cease to perform its functions: the water will go into the ground simply clarified, and not purified. This threatens the contamination of fertile soils, the spread of pathogenic bacteria, and even cases of disease among people and domestic animals.

You should not assume that one malfunctioning septic tank “means nothing” for the environment. Groundwater travels vast distances and feeds many hydraulic structures, incl. wells and wells. The consequences of dumping untreated wastewater into the soil are unpredictable (+)

If an underground aquifer on a site comes close to the surface, infiltration is possible: fecal bacteria will quickly end up in drinking wells and begin to spread further. Under unfavorable circumstances, this is fraught with real epidemics and livestock pestilence.

The logic of septic tank owners who drain water for the winter is clear: they fear that the liquid will freeze and rupture the tank body, but if the structure is installed correctly, this probability is extremely low.

The damage that can be caused by completely pumping out the chambers of a septic tank can be much greater, so you should not make this mistake.

The wishes of septic tank owners do not in any way affect the laws of physics. If a light bulk tank is empty, it may float up during spring floods

If you remove water from the chambers of a plastic or fiberglass septic tank, you may get an unpleasant surprise in the spring: the structure will float to the surface, breaking pipelines and raising soil. Correct installation reduces the risk of floating, but not as critically as the owners expect.

Step-by-step installation instructions are provided below.

Soils are not static; their movements are always possible, especially during periods of sudden temperature changes, changes in groundwater level or under the influence of other factors. Loads on the side walls and bottom of the tank can increase significantly.

Under soil pressure, an empty septic tank can either float or become deformed. In both cases, you will have to spend effort, time and money to restore the sewer system. If the building cannot be repaired, you have to buy a new treatment facility.

When installing a septic tank, they provide for the possibility of soil movement and protect the structure. Such measures are only necessary when installing fiberglass and plastic structures, because concrete structures are heavy and much less susceptible to external influences (+)

All these problems, unnecessary expenses and worries are easy to avoid. You just need to properly preserve the septic tank and take into account that in winter you may need to put it back into operation.

If the owner plans to visit a country house or dacha at least once a month, the treatment plant can be left “as is” - fully functional. Even an energy-dependent septic tank with running compressors will not burden the budget too much.

Rules for the conservation of treatment facilities

Usually, the operation of the septic tank is stopped with the first cold weather - as soon as the temperature drops to 0°C. It is important not to wait for frost and start preserving the treatment plant before the ground begins to freeze.

This period is considered the best, since the groundwater level has already dropped to a minimum level, and the soil has stabilized, which means that movements are practically excluded.

In the spring, by the time the septic tank is put into operation, there are not enough bacteria left to clean the wastewater to the required 95-98%. You can speed up their reproduction by pouring sour kefir down the drain or adding special biological products (+)

If all measures to preserve the septic tank for the winter are carried out correctly, enough viable bacteria will remain in the tanks, which will begin to multiply rapidly as soon as the first sewage with the necessary organic substances arrives.

Very quickly they will be able to process wastewater at the proper level, although at first the quality of treatment will not be the highest. To “help” bacteria, you can add a drug to the septic tank before starting the system "Doctor Robik".

Method 1: preparation of industrial septic tanks

Industrially produced septic tanks are convenient not only in installation and operation. The procedure for their conservation is described in detail in the technical documentation.

Each model has its own characteristics, so before stopping work you should carefully read the instructions.

Septic tanks are insulated only in regions where there are severe frosts. Almost any material is suitable for thermal insulation. The main thing is that the roof of the treatment plant is completely covered and the insulator is not exposed to external influences

There are several general rules that should be followed when mothballing any energy-dependent wastewater treatment plant:

• Blackout. Biological treatment stations are connected to the power grid. They are turned on and off using a special automatic switch in the house and/or a button on the control panel.
• Partial dismantling of electrical equipment. It is imperative to remove the compressor mounted in the working compartment. To do this, you need to disconnect the retaining clips.
• Dismantling the pump. Some models have a pump installed for forced pumping of filtered water. It also needs to be removed, inspected, cleaned and, if necessary, repaired.
• Water level measurement. For conservation, it is necessary that the septic tank tanks be filled to 2/3 or 3/4 of the total volume. If there is not enough liquid, you need to add the missing amount.
• Thermal insulation of the roof of a building. This is an optional event.It is performed only if there is a risk of the septic tank freezing. The roof is insulated with any available material - extruded polystyrene foam, polystyrene foam, straw, dry grass, sawdust, etc.

A properly preserved septic tank will not float and will not suffer from soil instability. It can be put into operation almost instantly - immediately after installing and connecting the compressor.

Before stopping the septic tank for the winter season, it is recommended to clean the airlifts and chambers and remove sludge deposits.

In regions with a harsh climate, it makes sense to install several floats in the chambers with liquid, which will protect against damage to the housing wall due to an ice crust.

The purpose of plastic floats is to reduce pressure on the walls of the structure’s body. It is advisable to make more of them. Ice compresses the floats, resulting in less stress on the liquid reservoir

Making floats for a septic tank is very easy. To do this, take several plastic drink bottles with a volume of 1.5-2 liters and pour sand into them to such a level that the containers are immersed in the liquid by about half and do not sink.

The finished floats are tied to a long nylon rope so that they can be easily pulled out if necessary. The rope itself is firmly secured from the outside.

Method 2: stopping the homemade design

An industrial septic tank is convenient, effective, but expensive. Many owners of summer cottages choose cheaper home-made structures. Usually these are non-volatile structures, the conservation of which may not pose any particular difficulties.

The septic tank is cleared of sludge. If any electrical equipment is installed (compressors, pumps, etc.), it is dismantled and preventative maintenance is carried out. If necessary, replenish the liquid level in the same way as in the case of an industrial septic tank - by 2/3 or 3/4 of the volume of the chambers.

There are fewer problems with the conservation of homemade concrete septic tanks. They just need to be inspected, cleaned and, if necessary, insulated.

Water level in septic tank made of concrete rings is not important, since the floating of such a structure is impossible due to the weight of the structure.

If insulation is needed, use special materials or straw, dry leaves, sand. If you use polystyrene foam boards, polyethylene or other insulators that do not allow air to pass through, several holes should be made so that aerobic bacteria receive the oxygen necessary for their life.

Conclusions and useful video on the topic

There are many types of septic tanks. Maintaining them and preparing them for winter is not always easy. Owners may have questions related to checking the fluid level in models without special sensors. Problems often arise with self-pumping of activated sludge.

We offer videos that will simplify the task of preserving wastewater treatment plants.

If you need to install a sensor that signals a high water level in the septic tank, you can assemble it yourself. The specialist explains how to do this:

Detailed video instructions for preserving a septic tank:

How to maintain a Topas septic tank without turning to a specialized company for help:

Spring re-opening of the treatment plant is simple. It is necessary to remove layers of insulation, remove floats, install compressors and pumps. All that remains is to connect the septic tank to the power grid and it will work.

Within a few days or weeks, the bacteria will “come to their senses”, and the efficiency of the treatment system will be the same as before conservation. The likelihood that microorganisms will have to be “reanimated” is low.

Do you have personal experience preparing a septic tank for wintering? Want to share your own methods or ask questions on the topic? Please leave comments - the feedback form is located below.