Soak Pit – Advantages, Disadvantages & Design,

What Is A Soak Pit?

A soak pit is an underground circular or rectangular porous chamber that helps soak the wastewater slowly into the ground.

As we know that the water in the septic tank, which is known as greywater, is not pure as they contain organic materials which need to be filtered, so it can’t be discharged directly into an open area.

soak pit

The Necessity Of Soak Pit

The effluent water comes from primary treatment units like septic tanks, anaerobic baffled reactor, a biogas settler. Twin pits etc., contain organic materials which require filtering before letting it into the ground.

As this water is not reusable, it gets soaked into the surrounding soil. So soak pit is necessary to discharge the effluent more safely into the environment. It also helps in recharging the groundwater table.


How Does Soak Pit Works?

A soak pit is usually built in a circular or rectangular chamber with pores at regular intervals. An effluent (wastewater from the toilet, kitchen, bathroom, etc.) carrying pipe connects it with the septic tank.

The pit is filled with boulders and gravels, so when the effluent is discharged to the soak pit, the filler materials filter the water and organic materials.

The water flowing into the soak pit is subjected to filtration, as the smaller particles or organic particles in the effluent get settled down at the bottom of the soak pit.

These small particles are later consumed or digested by the microorganisms. Then the filtered water gets slowly soaked into the surrounding soil. Soak pits are best suited for porous soils having high absorption or infiltration rate.

soak pit

Soak Pit Function

1. It collects effluent from the primary treatment unit.

2. The collected effluent undergoes partial treatment in the soak pit.

3. It discharges partially treated or non-harmful water into the surrounding soil.

4. It is also helpful in recharging the groundwater table.

5. Its sole function involves collecting and infiltrating the surface water into the ground and helps relink the earth to the below hydrological cycle.

Basic Design Consideration Of Soak Pit

Some primary considerations that must be taken while designing or constructing the soak pit, as follows:

1. The soak pit should be between 1.5m to 3m, but it must not be less than 2m above the groundwater table.

2. Soak pit must be located away from the drinking source, usually 30m distance away.

3. Must lay a layer of sand and gravel at the bottom to disperse the effluent flow.

4. We should not construct a soak pit nearer or in a high traffic area; failing to do so may lead to soil compaction.

5. A removable cover lid must be provided for any maintenance and repair works in the future.

6. The soak pit is either left empty or filled with boulders or gravel, which will help prevent walls from collapsing, but still has adequate space for wastewater.

7. The soak pit must be constructed where the site does not gather surface ruff off the water, which leads to clogging of the soak pit resulting in water stagnation.

Operation And Maintenance

1. A soak pit can last for three to five years without any proper maintenance.

2. It is possible to extend the durability of the soak with adequate Maintenance.

3. The soak pit eventually gets clogged by the filtered particles and biomass, so it must be removed and cleaned.

4. The filler materials like gravel or boulders require replacement over a certain period.

 5. A removal lid having sufficient space for cleaning must be provided to access the soak pit.

Health Aspects

1. Soak pits are generally constructed under the ground, so chances of human and animal contact with them are very low.

2. It must be located away from the drinking water source, usually 30 m away. Failing to do so may result in contamination of drinking water.

3. It can be adopted in even sensitive communities as they are odorless and have less contact with humans.

Advantages Of Soak Pit

1. Construction of soak pit is possible with locally available materials.

2. Easy to construct and operate, Anyone can adopt this technique.

3. The installation area requirement is small.

4. It helps in recharging the groundwater table

5. The soak pit technique is power conservative and sustainable.

6. Soak pit is best suited for rural areas, where there is a lack of municipal drainage.

7. Initial capital investment is significantly less, and anyone can afford it.

Disadvantages Of Soak Pit

1. It requires primary treatment to prevent clogging.

2. The discharge might negatively affect the groundwater and soil properties if the effluent is highly toxic.

3. Soak pit is not suitable for clod climate areas.

4. Soak pits are not suitable if the daily effluent discharge volume is high.

5. Not suitable, where the soil has low absorption or infiltration rate.

6. It is suitable if the groundwater table is at least two meters below the soak pit.

7. Soak Pit is not suitable for high traffic areas.


Soak pit is essential as they play a vital role in keeping the environment hygienic and disease-free. Usually, in rural areas where people are less aware of the health and hygiene of the surrounding. If failing to consider all these aspects may lead to severe health and environmental problems.


What is the difference between the Soak pit and the Septic tank?

Ans- Often, people are confused that both are the same, but no, As the soak pit and septic tank have similar functionality to some extent like water treatment, and both are used as drainage systems built underground.

But the water in the soak pit generally gets soaked into the surrounding soil. In contrast, the effluent is usually removed by the pumping machine or sewerage vehicle in the septic tank.

Soak pit is usually built with locally available materials, but the septic tank is constructed using bricks and cement, and even a concrete floor bed is laid.

Also Read –

Septic Tank Shape, Size, And Dimensions

What Is Waterlogging & Its Causes?

If you like this article then please share it with your friends & also like our Facebook Page and join our Telegram Channel.

Leave a Comment