Septic tanks for a private house: how to choose, installation, price


What is the best septic tank?

It is con­ve­nient when a pri­vate house is con­nect­ed to a cen­tral­ized sew­er­age sys­tem. But if this is not pos­si­ble, then you should think about installing a local waste dis­pos­al sys­tem — a sep­tic tank.

It allows you to save the site from pol­lu­tion, and in some cas­es it makes it pos­si­ble to obtain process water from waste­water for water­ing plants, wash­ing cars, etc.

At the same time, the oper­a­tion of the sep­tic tank is based on a sim­ple prin­ci­ple.

How does a septic tank work?

What­ev­er the clean­ing device, its oper­a­tion is based on 3 prin­ci­ples:

  • sed­i­men­ta­tion of large sus­pen­sions;
  • floata­tion of light pol­lu­tants;
  • bio­log­i­cal decom­po­si­tion.

How a septic tank works

All sep­tic tanks con­sist of sev­er­al cham­bers. The first 2 stages of clean­ing take place in the first tank. The branch pipe lead­ing to the next cham­ber is locat­ed in the cen­ter, drain­ing water, in which there are no longer sus­pend­ed sus­pen­sions and heavy frac­tions. The type of biodegra­da­tion and its effec­tive­ness depends on the type of appa­ra­tus.

On the video you can see the process of water purifi­ca­tion in a sep­tic tank:

Types of septic tanks for a private house

The clas­si­fi­ca­tion of the waste­water treat­ment sys­tem into types is based on the depen­dence on elec­tric­i­ty, the type of biodegra­da­tion and the mate­r­i­al from which the sep­tic tank is made.

Anaerobic and aerobic varieties

In sim­pler designs, anaer­o­bic (oxy­gen-free) decom­po­si­tion of con­t­a­m­i­nants occurs in the sec­ond and sub­se­quent tanks. Such clean­ing is not com­plete and requires an addi­tion­al stage of soil fil­tra­tion: fil­tra­tion wells or fil­tra­tion fields.

Types of septic tanksIn them, the remain­ing con­t­a­m­i­nants are retained by the fil­ter­ing back­fill, on which a film of microor­gan­isms is addi­tion­al­ly formed, con­tin­u­ing the process of bioox­i­da­tion.

Local treat­ment plants more com­plex and effi­cient designs. They mim­ic large sew­er efflu­ent treat­ment sys­tems.

There are also sev­er­al cam­eras in the LOS. In addi­tion to set­tling and anaer­o­bic decom­po­si­tion, such a device has a com­part­ment in which aer­o­bic microor­gan­isms (acti­vat­ed sludge) break down pol­lu­tion in the pres­ence of oxy­gen.

After that, the water enters a spe­cial sump for the set­tling of acti­vat­ed sludge, which is pumped out by the air­lift into the sta­bi­liza­tion com­part­ment. Part of the sludge mass is again fed into the aer­o­bic treat­ment tank. Pre­cip­i­tat­ed dense sludge must be peri­od­i­cal­ly removed from the tank.

There are also stor­age tanks in which water does not under­go any treat­ment oth­er than pre­cip­i­ta­tion. They only col­lect and peri­od­i­cal­ly remove waste­water. Accu­mu­la­tors can only con­di­tion­al­ly be called a sep­tic tank, this is a cesspool — a cheap option to install, suit­able only for small coun­try hous­es with a small amount of drains.

Dependence on electricity

Volatile septic tanksIt is impor­tant to know this prin­ci­ple of clas­si­fi­ca­tion of waste dis­pos­al sys­tems, since not all coun­try hous­es have access to an unin­ter­rupt­ed sup­ply of elec­tric­i­ty.

  1. non-volatile are sim­ple devices where anaer­o­bic oxi­da­tion of organ­ic mat­ter is car­ried out, and water is poured between reser­voirs and to the stage of soil post-treat­ment by grav­i­ty.
  2. VOCs do not work with­out elec­tric­i­tynec­es­sary for the oper­a­tion of the com­pres­sor sup­ply­ing air. Also, in many mod­els, waste­water from one cham­ber to anoth­er and acti­vat­ed sludge are pumped by air­lifts pow­ered by a com­pres­sor.

Anaer­o­bic devices depend on elec­tric­i­ty when, due to the nature of the land­scape, it is nec­es­sary to install a pump to trans­fer liq­uid to the soil fil­tra­tion stage.

What and how to make a septic tank?

Waste treat­ment tanks can be made from a vari­ety of mate­ri­als.

  1. There is fin­ished plas­tic tanks. You can also make them your­self from sev­er­al large-diam­e­ter plas­tic pipes or eurocubes. Mount­ing such con­tain­ers is quick and easy, with­out the involve­ment of spe­cial equip­ment. They are durable and have become very pop­u­lar late­ly.
  2. met­al con­tain­ers may be ready. They can also be weld­ed from sev­er­al sheets. Such tanks are rarely used, main­ly when it is nec­es­sary to place the con­tain­er at a great depth. From the inside, to extend the life of the con­tain­er, it is rec­om­mend­ed to treat it with an anti-cor­ro­sion com­pound.
  3. brick — bud­getary, but phys­i­cal­ly expen­sive mate­r­i­al. The brick is laid on a con­crete base. The cross sec­tion can be round and with right angles.
  4. Sep­tic tanks from con­crete rings — one of the most tra­di­tion­al options. Prod­ucts with a diam­e­ter of about 1 m are used, which are installed on top of each oth­er. For their deliv­ery and instal­la­tion, it is nec­es­sary to hire a truck and a crane. Con­crete con­tain­ers often leak at the junc­tion.

From concrete ringsBud­get, but not very reli­able tanks are made of wood, tires from truck wheels.

When choos­ing the type and mod­el of the device, it is nec­es­sary to cor­rect­ly make cal­cu­la­tions, take into account the fea­tures of the site.

An impor­tant fac­tor is the price of the fin­ished sta­tion.

How to choose a septic tank for a private house?

The sim­plest and most reli­able option is a ready-made plas­tic sep­tic tank. There are enough com­pa­nies offer­ing such prod­ucts now. Before buy­ing or self-con­struct­ing a sep­tic tank for a toi­let, you need to decide on sev­er­al para­me­ters.


The required capac­i­ty and vol­ume are deter­mined by the num­ber of inhab­i­tants. If guests will peri­od­i­cal­ly live in the house, then they must also be tak­en into account in the cal­cu­la­tions. On aver­age, one per­son gen­er­ates 200 liters of waste­water per day.

For a fam­i­ly of four, equip­ment with a capac­i­ty of 800 liters is required. Since waste­water can be in the tanks for 3 days, then pow­er received must be mul­ti­plied by 3to get the vol­ume val­ue. For our exam­ple, we need tank with a vol­ume of 2.4 m3.

natural conditions

How much does a septic tank cost?Fea­tures of the relief, soil and cli­mat­ic con­di­tions are also impor­tant not only at the instal­la­tion stage, but also at the pur­chase stage.

  1. You need to know the depth of soil freez­ing, because the pipeline and its entrance to the tank must be below the zero point. There are spe­cial ready-made mod­els with an elon­gat­ed neck and a low inlet.
  2. Samo equip­ment is rec­om­mend­ed to be installed where there is an ele­va­tion to pro­tect against atmos­pher­ic mois­ture.
  3. If the land­scape does not allow grav­i­ty to remove efflu­ent from the reser­voirthen you need to choose a mod­el with forced evac­u­a­tion of the puri­fied liq­uid, in the last cham­ber of which the pump is locat­ed.
  4. For clay soils prone to burst­ing dur­ing freez­ing we need struc­tures with espe­cial­ly strong walls: con­crete, plas­tic with stiff­en­ers.
  5. For soil post-treat­ment, it is espe­cial­ly impor­tant to know the type of soil. The best option is sandy soil. In oth­er cas­es, the arrange­ment of fil­tra­tion fields requires a lot of effort.

Cost and popular models

Tank 2.5

Pho­to — Tank 2.5

Each own­er takes into account the price of the waste dis­pos­al device. But here it is bet­ter not to save.

The best option is to pur­chase ready-made equip­ment.

Below are prices for pop­u­lar mod­els designed to serve 4–5 peo­ple.

  1. Pop­u­lar sep­tic tank with soil aftertreat­ment Tank 2.5 in full set from 360 $.
  2. Proven Poplar 5relat­ed to com­plete bio­log­i­cal treat­ment plants, can be pur­chased at least 720$.
  3. Topas 5 also pro­vides a high degree of waste­water treat­ment. The cost of such equip­ment about 800 dol­lars.
  4. If you are look­ing for a sep­tic tank for a sum­mer res­i­dence, then a good option could be “Tri­ton-mini”, with a vol­ume of 750 liters. Togeth­er with the soil fil­tra­tion sys­tem, it costs about 220 $.
  5. More and more pos­i­tive reviews are gain­ing and LOS “Uni­los Astra‑5”. You can become the own­er of this sys­tem for about 800 $.

Many users have already seen the reli­able oper­a­tion of these devices. In addi­tion, they are all sim­ple and for self-assem­bly.

Device and installation of septic tanks

Installing a waste­water treat­ment device is quite sim­ple, espe­cial­ly a ready-made plas­tic con­tain­er, to which instruc­tions are attached. First you need to choose the right place.

  1. From the foun­da­tion the house to the sep­tic tank must be at least 5 meters. But you don’t need to install too far, oth­er­wise you need a revi­sion well.
  2. Dis­tance between trees and a sep­tic tank 3 m.
  3. From rivers and reser­voirs to the waste­water treat­ment device should be 30 m, and from wells and wells — 50 m.
  4. Roads should not pass over the fil­tra­tion fields.

As men­tioned above, it is impor­tant to know the depth of soil freez­ing, which is indi­cat­ed in SNIP 2.02.01–83 * for each region of the coun­try. Pipes and soil fil­tra­tion ele­ments must be locat­ed below the zero tem­per­a­ture point.

Installation scheme Tank 2.5

Instal­la­tion scheme Tank 2.5

Based on all these data, a sep­tic tank is installed in accor­dance with with step by step instruc­tions.

  1. They dig trench­es under a slope for pipes and a foun­da­tion pit for the sep­tic tank itself.
  2. A lay­er of sand 10 mm thick is poured into the ravines, it is rammed, always observ­ing the slope.
  3. Con­struct a sand and, if nec­es­sary, a con­crete cush­ion in the pit. It must be even.
  4. Install a sep­tic tank exact­ly.
  5. Con­nect it to the sup­ply pipes, as well as a pipeline lead­ing to soil fil­tra­tion or a col­lec­tion tank.
  6. Fall asleep pipes and tank. It is impor­tant to pour liq­uid into the con­tain­er, the water lev­el should be 150 mm above the back­fill lev­el.

Sprin­kle the tank with a mix­ture of cement and sand, and the last 30 cm with soil. After that, the sys­tem is ready for start-up and oper­a­tion.

Watch a video on how to make a sep­tic tank with your own hands:

Septic tank maintenance: price

Plas­tic tanks do not require spe­cial care.

  1. Once a quar­ter, the VOC eval­u­ates the sludge. If it is dark and begins to thick­en, then it must be removed. To do this, you can use a sim­ple drainage pump.
  2. Once every 1–2 years, it is nec­es­sary to pump out the sed­i­ment from the sump using a sewage machine. At this time, it is rec­om­mend­ed to flush the entire tank.
  3. Once a week it is worth look­ing into the hatch of the tank to eval­u­ate the work. This is espe­cial­ly true for aer­o­bic instal­la­tions.

Cleaning septic tanksYou can con­clude an agree­ment with a spe­cial­ized orga­ni­za­tion for main­te­nance. A one-time pro­ce­dure with sludge pump­ing and equip­ment revi­sion costs at least 40 dol­lars. The min­i­mum cost of annu­al main­te­nance is 150 $.

The full range of works and the price for them depends on the mod­el.

Which is better: model characteristics

Mod­el name Pro­duc­tiv­i­ty, m3/day Vol­ume, m3 Dimen­sions Price, thou­sand rubles
Euro­bion 4 0.8 0.25* 1.0x1.0x2.3 67
Euro­bion 5 0.9 0.39* 1.1x1.1x2.4 71
Tank 2 0.8 2.0 1.8x1.2x1.7 29
Tank 2.5 1.0 2.5 2.0x1.2x1.9 33
Tri­ton mini 0.5 0.75 1.3x0.8x1.7 19
Tri­ton-ED 0.6–1.2 1.8 1.2x1.2x1.7 23
Poplar 5 1.1 0.25* 1.0x1.0x2.5(3.0) 80
Poplar 8 1.9 0.47* 1.3x1.0x2.5(3.0) 95
Astra 5 one 0.25* 1.1x1.1x2.4 72
Astra 8 one 0.35* 1.5x1.2x2.4 90

*for VOCs, the vol­umes of sal­vo release are indi­cat­ed.

Installation cost

If you decide to install a sep­tic tank inex­pen­sive­ly, i.e. inde­pen­dent­ly and chose a ready-made plas­tic mod­el, the cost of the fin­ished struc­ture will depend on the price of the mod­el, sand, cement and pipelines.

You can order the instal­la­tion of a turnkey clean­ing sys­tem. The min­i­mum cost of such a ser­vice is 210 $.

But hav­ing invest­ed once, you will ensure the reli­able oper­a­tion of the treat­ment equip­ment and the clean­li­ness of the site itself.

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