Scheme and wiring of sewerage in a private house


You can feel all the advan­tages of liv­ing in a pri­vate house only if the util­i­ties work prop­er­ly. Prop­er wiring of sew­er­age in indi­vid­ual hous­ing cre­ates com­fort­able con­di­tions, and prob­lems in the oper­a­tion of the waste­water dis­charge sys­tem cause a lot of trou­ble.

The arti­cle tells how to make sew­er wiring in a pri­vate house or in the coun­try with your own hands with­out errors.

Components of the sewer

Accord­ing to the pur­pose of the liq­uid waste dis­pos­al net­work, there are:

  • inter­nal;
  • exter­nal;
  • storm.
The main ele­ments of the sew­er design.

A detailed project, strict com­pli­ance with the require­ments of the doc­u­ments will help to avoid and, if nec­es­sary, quick­ly elim­i­nate mal­func­tions that lead to unpleas­ant work with “escaped” feces.


A pre­lim­i­nary scheme is drawn up at the design stage. In the future, this will save you from car­ry­ing out labor-inten­sive oper­a­tions for punch­ing tech­no­log­i­cal holes in ceil­ings and walls for lay­ing sew­er pipes.

The project defines the equip­ment and devices, the places of their con­nec­tion to the sew­er­age.

A detailed dia­gram reduces the num­ber of trips to a spe­cial­ized store for miss­ing parts.

Wiring dia­gram for deter­min­ing the num­ber of pipes and fit­tings.


If the work is entrust­ed to be per­formed by a third-par­ty orga­ni­za­tion, then the project will sim­pli­fy the con­trol over the reli­a­bil­i­ty of the esti­mates in the sec­tions “mate­ri­als” and “work per­formed”.

Mate­r­i­al selec­tion

The prod­uct range allows you to cre­ate com­mu­ni­ca­tions of any com­plex­i­ty and con­fig­u­ra­tion — man­u­fac­tur­ers pro­duce: pipes of var­i­ous lengths and diam­e­ters, adapters, con­nec­tions, angles and turns, fit­tings for con­nec­tion. All of them are called shaped parts (styling).

For sew­er­age in an indi­vid­ual res­i­den­tial build­ing, they choose between cast-iron or plas­tic prod­ucts avail­able for pur­chase. Stain­less and steel com­mu­ni­ca­tions in indi­vid­ual con­struc­tion have not received dis­tri­b­u­tion due to the high cost and fea­tures of instal­la­tion, which can­not be car­ried out with­out spe­cial weld­ing equip­ment.

Cast iron

Cast iron sew­ers are also rarely used in sew­er­age lay­outs in pri­vate homes:

  • com­po­nents are much more expen­sive than plas­tic ones;
  • the mass of pipes makes trans­porta­tion dif­fi­cult;
  • instal­la­tion is impos­si­ble with­out a team of assis­tants;
  • for seal­ing joints, pack­ing and cement put­ties are used, which is not tech­no­log­i­cal­ly advanced;
  • con­nec­tion, not pro­vid­ed for by the orig­i­nal plumb­ing project, is dif­fi­cult with­out par­tial destruc­tion of the entire struc­ture.

Cast iron prod­ucts are suit­able for instal­la­tion in cold rooms, as they can be heat­ed with a blow­torch when frozen.

Cast iron fit­tings.

In indi­vid­ual con­struc­tion, cast-iron pipes marked ChK (cast-iron sew­er) and mod­ern mod­els for sock­et­less instal­la­tion, called SML, are used. The lat­ter have a much low­er mass, and clamps are used for con­nec­tion. It is allowed to use cast iron prod­ucts marked VSHCHG and ChNR, but these are spe­cial­ized prod­ucts for pres­sure water sup­ply and under­ground sewage, their cost is high, and at home they are used only if they were able to pur­chase “for a song”.


Plas­tic pipes and acces­sories:

  • durable;
  • do not require seal­ing joints;
  • easy to install by one per­son
  • unaf­fect­ed by aggres­sive liq­uids.

When buy­ing, take into account that “plas­tic” is of three types:

  1. Poly­eth­yl­ene prod­ucts are cheap­er than oth­er types, but it is unde­sir­able to use them to install sew­ers in the premis­es of the house. Pipes are sub­ject to defor­ma­tion dur­ing tem­per­a­ture changes, while the tight­ness in the joints is bro­ken. How­ev­er, the mate­r­i­al is UV resis­tant, so it is suit­able for storm sew­ers.
  2. The cost of com­po­nents made of poly­iso­propy­lene is high, but they are not sub­ject to defor­ma­tion when exposed to tem­per­a­ture, they can be cleaned with met­al brush­es, chem­i­cals do not harm.
  3. Sew­er­age made of polyvinyl chlo­ride (PVC) is the best choice in terms of price and con­sumer prop­er­ties. The dis­ad­van­tages include the inabil­i­ty to use met­al brush­es when clean­ing. Boil­ing water enter­ing the sew­er leads to defor­ma­tions. But, it is dif­fi­cult to imag­ine such a case — no one takes a bath at a water tem­per­a­ture above 80aboutC. It is impos­si­ble to heat pipes with an open flame in case of freez­ing, there­fore polyvinyl chlo­ride is not used in unheat­ed rooms.

The joints of PVC pipes and stan­dard fit­tings with­out threads are reli­ably sealed with spe­cial rub­ber (sil­i­cone) rings. To facil­i­tate assem­bly, they pur­chase sil­i­cone sealant for plumb­ing. The com­po­si­tion of the “seal” includes addi­tives that pre­vent the devel­op­ment of fun­gi and mold at the joints.

PVC prod­uct range.


There is, but not wide­ly used, sock­et­less sys­tems, when the con­nec­tion is made by glu­ing. The dis­ad­van­tage is that it will not work to change the assem­bled struc­ture with­out mechan­i­cal destruc­tion.

The diam­e­ter of sew­er pipes and fit­tings depends on the con­nect­ed equip­ment. The rec­om­mend­ed sizes are col­lect­ed in the table.

San­tekh­pri­bor Min­i­mum inner diam­e­ter, mm
Wash­ing fifty
Wash basin fifty
Wash­ing machine 32
Dish­wash­er 40
Toi­let 100
Drain for heat­ing appli­ances 32
Ris­er in a one-sto­ry house 100
Ris­er in a two-sto­ry build­ing 150

“Advice! When choos­ing a mate­r­i­al, try to choose com­po­nents from the same man­u­fac­tur­er — even small man­u­fac­tur­ing tol­er­ances cause instal­la­tion dif­fi­cul­ties due to dif­fer­ent, by 1–2 mm, diam­e­ters.

Installation rules

When start­ing work on your own or to con­trol the work of builders, it will not be super­flu­ous to famil­iar­ize your­self with the require­ments of the Code of Rules (SP) and SNiP (san­i­tary norms and rules):

  • SP 30.13330.2012. “Inter­nal water sup­ply and sew­er­age of build­ings” is the cur­rent edi­tion of “SNiP 2.04.01–85”.
  • SP 32.13330.2012, “SNiP 2.04.03–85. Sew­er­age. Exter­nal net­works and struc­tures”.

The codes of prac­tice were approved in 2012, but the require­ments of SNiPs of 1985 are almost repeat­ed in them. The doc­u­ments con­tain com­plete infor­ma­tion on all stages of work. Extracts impor­tant for the con­struc­tion of a pri­vate house are col­lect­ed in the fol­low­ing sec­tions of our arti­cle.

Required Tools

The set of tools for self-wiring sew­er pipes in a one-sto­ry pri­vate house is small, you will need:

  • per­fo­ra­tor with bits for con­crete and a chis­el;
  • angle grinder (grinder);
  • sealant gun and plumb­ing sealant;
  • roulette;
  • build­ing lev­el;
  • file.

Laying external networks


The drain from the house should be 10 — 15 cm low­er than the lev­el of freez­ing of the earth; in cold areas, ther­mal insu­la­tion of the pipeline is pro­vid­ed.

“Impor­tant! For drain­ing, pipes intend­ed for lay­ing in the ground are select­ed. It is bet­ter to use ceram­ic or cast iron pipes. Plas­tic mate­ri­als intend­ed for out­door use are paint­ed light brown or orange.

At the design stage, access roads for sewage trucks are pro­vid­ed; they should not pass over pipelines.

The branch is mount­ed, observ­ing a slope of 2 — 3 cm / m in length. A 15 cm sand cush­ion is arranged in advance, which should also be placed on top of the pipe before fill­ing the trench with soil.

Mount­ing the out­let on a sand bed.

A tech­no­log­i­cal hole is pro­vid­ed in the foun­da­tion, where a steel sleeve is mount­ed on the cement mor­tar, the diam­e­ter of which is 15–20 cm larg­er than the cross sec­tion of the out­let pipe. The edges of the sleeve should pro­trude 150 mm beyond the out­er and inner edges of the foun­da­tion. After the final instal­la­tion, the gap is sealed with mount­ing foam, and the out­er side of the foun­da­tion is equipped with water­proof­ing.

“Impor­tant! The ris­er with the out­let is con­nect­ed by turn­ing 45about. Con­nec­tion angle 90about often leads to block­ages in cor­ners.

Connection to a septic tank

The per­mit­ted dis­tance from the sep­tic tank to the foun­da­tion is at least 5, and to the out­build­ings 3 meters.

The pipe inlet in the stor­age tank is locat­ed in the upper third of the wall of the sep­tic tank (well) — this will exclude water back­wa­ter into the house when the stor­age tank is over­filled or the cen­tral­ized net­works are clogged.

The top cov­er of the sep­tic tank of the pit is equipped with an exhaust hood to remove gas­es. Oth­er­wise, unpleas­ant odors enter the house.

Cor­rect con­nec­tion of the out­let to the sep­tic tank and the exhaust scheme.

Internal networks


Instal­la­tion of inter­nal net­works is car­ried out in three stages:

  • ris­er instal­la­tions;
  • instal­la­tion of an extract (fan pipe);
  • wiring of inter­nal net­works to plumb­ing fix­tures.

At the ini­tial stage, a rough assem­bly is car­ried out for an accu­rate fit. If all the con­nec­tion points are in the places pro­vid­ed, the final instal­la­tion is car­ried out.

Rules for installing a central riser

Unlike apart­ments in a pri­vate house, depend­ing on the project, sev­er­al ris­ers can be installed. The exact amount is affect­ed by how far apart the sources of dirty water are in space, the num­ber of bath­rooms.

“Impor­tant! The dis­tance from the toi­let bowl to the ris­er can­not exceed 1 meter, to oth­er devices 3. If the project of the house does not allow to with­stand these dis­tances, then sev­er­al cen­tral ris­ers are made.

Instal­la­tion starts from the out­let, the sock­ets of the seg­ments are set upwards, this cre­ates less resis­tance to the move­ment of drains.

Imme­di­ate­ly after turn­ing, the revi­sion is mount­ed. This will allow clean­ing with­out dis­man­tling the entire struc­ture — the pipes enter the sock­et by about 10 cm and the entire ris­er will have to be raised, and this can­not be done with the sys­tem installed.

It is advis­able to install a revi­sion on all floors of the build­ing.

“Atten­tion! The ris­er is mount­ed strict­ly ver­ti­cal­ly. The max­i­mum allow­able slope is 1 cm/m of pipe length.

In the ceil­ings between floors, the ris­er is fixed with cement mor­tar. In a wood­en house, mount­ing foam is used.

The ver­ti­cal sec­tions of the ris­er are attached to the walls with clamps, which are mount­ed in advance so that the pipes do not inter­fere with drilling.

At the con­nec­tion points of plumb­ing fix­tures, tees with out­lets of the required diam­e­ter are mount­ed.

After the final assem­bly, the ris­er is wrapped with sound­proof­ing mate­r­i­al and hid­den (if nec­es­sary) with fin­ish­ing mate­r­i­al (dry­wall, pan­els).


The hood (cor­rect­ly — a fan pipe) is equipped to remove an unpleas­ant odor from the sew­er pipes and pre­vent air jams. In fact, the fan pipe is a con­tin­u­a­tion of the ris­er.

The upper end of the hood is made high­er than the visor and pro­tect­ed from pre­cip­i­ta­tion by a visor.

San­i­tary stan­dards deter­mine the dis­tance from the out­let of the fan pipe to win­dow open­ings and bal­conies of at least 4 m.

In a sew­er with­out an exhaust hood, a vac­u­um is cre­at­ed in the pipes, which “pulls” water from the water seals, and the smell from the sep­tic tank (well) enters the house.

One-sto­ry res­i­den­tial build­ings are allowed to be built with­out a hood.

Wiring of internal networks

Prop­er wiring pro­vides for the ful­fill­ment of the require­ments:

  1. The hor­i­zon­tal lev­el of the toi­let bowl drain on each floor is locat­ed below any oth­er plumb­ing fix­ture — this will pre­vent water from enter­ing them from the tank when drain­ing.
  2. It is desir­able to exclude turns of 90 from the sys­tem.aboutif nec­es­sary, it is bet­ter to replace from two angles of 45about.
    Replac­ing a 90° turn with two 45° cor­ners.


  3. The toi­let bowl is con­nect­ed with a pipe with an inner diam­e­ter of at least 100 mm.
  4. The diam­e­ter of the out­let pipes from any device can­not be thin­ner than the receiv­ing one.
  5. Elbows with a length of more than 3 m are made of pipes equal in diam­e­ter to the ris­er. Oth­er­wise, an air vac­u­um is cre­at­ed that pre­vents nor­mal drain­ing. It is allowed to install an air valve at the end of the out­let pipe to allow air into the sys­tem.
  6. Dur­ing instal­la­tion, a slope of 20 — 30 mm / m in length for pipes up to 50 mm, and more than 2 cm / m for 100 mm prod­ucts, is observed.

    Min­i­mum slopes.
  7. Pipes of dif­fer­ent diam­e­ters are con­nect­ed through adapters.
  8. When assem­bling, it is advis­able to use a sealant with anti­fun­gal and antibac­te­r­i­al addi­tives.
  9. The eye­lin­er must be attached to the walls so that they do not hang in the air — oth­er­wise there are bends in the pipes at the joints and the tight­ness is bro­ken.
  10. Plumb­ing drains must be equipped with siphons (water seals) that pre­vent the pen­e­tra­tion of odors. Sinks are rec­om­mend­ed to be equipped with “bot­tle” type siphons, which pre­vent large par­ti­cles of food residues from enter­ing the sew­er­age sys­tem.
  11. Plas­tic pipes and fit­tings are iso­lat­ed from heat­ing devices — high tem­per­a­tures will melt the mate­r­i­al, con­nec­tions will lose their tight­ness, and cor­ro­sion of the heat­ing sys­tem is pos­si­ble from leak­ing water.
  12. The den­si­ty of the joints must with­stand the required pres­sure of the drains.

Storm sewer

The diam­e­ter of the drains is cho­sen based on the max­i­mum amount of pre­cip­i­ta­tion. At the same time, atten­tion is paid to the area of ​​u200bu200bcovering the roof — the larg­er it is, the larg­er the diam­e­ter of the pipes. Oth­er­wise, flu­id may accu­mu­late in the pipe with a simul­ta­ne­ous increase in the load, which threat­ens to destroy the struc­tures.

The main ele­ments of the storm drain.

The storm drain must be fixed to the wall with clamps

“Impor­tant! The drain from the storm sew­er is divert­ed away from the house. Dis­charge into the pub­lic (cen­tral­ized) sew­er is strict­ly pro­hib­it­ed.”

Strict obser­vance of the require­ments for the con­struc­tion of sew­er­age in a pri­vate house is a pre­req­ui­site for its long reli­able oper­a­tion, reliev­ing own­ers of main­te­nance headaches for many years.


Leave a Reply

You May Also Like