# How to choose the right septic tank size for a private house?

**Interested in the following question:**

- What size septic tank do I need for my home?
- How to choose the right size of a septic tank so that later there will be no problems?
- What to consider when choosing a septic tank?
- What should you look for when buying a home with a septic tank?

*Now there is a lot of information and advice on choosing a septic tank, but I still cannot find information that could help determine how to choose the right size of a septic tank.*

Share

## Archi

## The choice of a septic tank by volume

The volume of the septic tank should be

calculated using the formula:V is the volume of the septic tank, K is the number of residents, Q is the water consumption of one person per day (from 100 to 200 liters), 3 is a coefficient denoting a three-day settling of drains. This is how long it takes for all the particles in the water to either float up or settle to the bottom.

## Biological treatment station

There is nothing left to do but blindly trust the manufacturer’s figures.

See what daily consumption the biological treatment plant processes according to the declared characteristics and compare it with your calculated daily water consumption at the rate of 100-150 l / day per person.

## Kirromant

Well, with the size of a septic tank, it is more or less clear. But with what material is it better to have a septic tank for the sewage system?

And can someone advise a company that sells septic tanks and install them in country houses? Interested in companies that work in the Kiev region.

## Archi

They are engaged in the sale and manufacture of septic tanks for sewerage both for a private house, as well as for industrial enterprises. You can contact them and ask them to advise you and help you choose the volume of the septic tank.

## Doom

Not so long ago, I was also worried about the question of which septic tank to choose. At first I planned to install an autonomous sewage system, but in the end I weighed all the pros and cons. We opted for a conventional septic tank. We have 5 people living in our house, two of them are children. We have an ordinary septic tank made of concrete rings, that’s enough for us.

## Kirromant

A septic tank made of concrete rings is not suitable, the degree of purification is too low.

A septic tank like yours has a purification degree of only 55%.You can’t just drain the water. Yet I’m looking for a better solution than just a septic tank. Thanks for sharing.## Maroo

## Calculation of the volume of the septic tank by the number of people living in the house

The volume of a septic tank directly depends on the intensity of use of a residential building. We also take into account the number of residents and the number of plumbing units.

When calculating, we take into account that the volume of the septic tank is the total volume of all chambers, we also mean that in the first chamber the average height of solid deposits will be 20% of the height of the chamber. We subtract this volume from the calculations.

When calculating the volume of wastewater, the daily water consumption per person should be equal to –

0.2 m³ per day. And the volume is calculated taking into account a three-day supply. Then the minimum volume for one person is 0.6 m³, for afamily of 4 people– 2.4 m³, taking into account bottom sediments – 2.7 m³.## How to calculate the volume of a septic tank?

For the correct calculation of the size of the future autonomous septic tank of the sewerage system of the cottage, it is important to consider the following points:

Volume (by number of people):Width and depth. Here it is worth starting from whether there is enough area of the site to install a large cleaning system. If the site is small, then it is better to use a narrow and high septic tank. A concrete pipe, the length of which should be at least 2.5 meters, can help.

## Masteris

## Table of Required Septic Tank Size Based on Daily Waste-Water Volume in Gallons

Average Sewage WastewaterFlow – Gallons Per Day

Minimum Septic Tank Size in Gallonsof Effective Capacity Needed (1)

## Table of Required Septic Tank Size Based on Number of Bedrooms in a Home

How big does our septic tank need to be based on the number of bedrooms in the home? Some jurisdictions use the number of bedrooms rather than number of occupants or estimated daily wastewater flow to guide homeowners and septic installers in choosing a septic tank size.

## Septic Tank in Gallons Size Based on Number of Bedrooms

Number of bedroomsMinimum Septic Tank Capacity (Gallons)Minimum Septic Tank Liquid Surface Area (sq.ft.)## Devid

## Types of septic tanks that are often used in the house

Conventionally, all treatment facilities for the home can be divided into 3 groups:

Accumulation tanks– it does not matter what they will be made of, their function is the same – to accumulate sewage in themselves before the arrival of the sewer truck. Relatively cheap, easy to install, maintenance-free. The use is limited by the useful volume of the tank, hence the need for economical use of water and linking to the services of sewers. It is inconvenient and expensive. They are used only when soil and other conditions do not allow the installation of structures from the following two groups;Sedimentation tanks– multi-section tanks that do not require an electrical connection for settling waste water and their anaerobic purification. Microbiological purification processes proceed slowly in an oxygen-depleted environment.The water at the outlet has a characteristic odor and is purified by a maximum of 60%, so it must be purified. For this, fields or filtration wells are used: wastewater seeps through the soil layer, after which it does not pose a threat to the environment.

The sedimentation tanks are simple and affordable, but demanding to maintain. They must be periodically cleaned of the accumulated sediment, and the filtration field must be redone every 5 years. This solution is not suitable for a high groundwater table and soil with poor flow capacity, for example, clay;

Aeration stations– are the most advanced sewerage systems for cleaning households. drains. In the process of settling, aeration and the use of microorganisms, the drains are cleared by more than 90%, have no odor, they can be drained into roadside ditches. However, such stations require connection to the mains, their efficiency suffers during power outages. Plus, they are expensive and need qualified service.It should be noted that the volume of a septic tank is the sum of the volumes of all its chambers. Also, the volume is calculated from the bottom to the level of the pipe. For the first chamber – from the bottom to the overflow pipe between the chambers, and for the second chamber – to the drain pipe to a drainage well or to filtration fields.

It should also be borne in mind that in the first chamber the average height of solid deposits will be 20% of the chamber height. This volume must also be subtracted from the calculations if we are talking only about the liquid component.

## Kirromant

What kind of sewage system do you use for wastewater treatment? About the types of septic tanks and sewers, I know I am more interested in the question: how to choose the right volume of a septic tank and I want to select and buy the sewer itself.

## Dodoo

In order to correctly calculate the volume of a septic tank for sewerage, it is necessary to take into account all the needs of the owners of a country house, while taking into account the area they occupy. To calculate the volume of a septic tank,

the following indicators are used:Having calculated these parameters, you can calculate the approximate volume of a septic tank that will suit your home.

The volume of the septic tank to be installed should be selected according to the following parameters:## Junior

The volume of the septic tank directly depends on the number of people living in the house. In order for the sewage system to be effective, you need to choose the optimal size of the septic tank for the house.In order to choose the optimal size of the septic tank, you can use the calculation formula.

V is the total volume of the septic tank in m3

N is the estimated number of people living in the house

Q is the volume of water that is used by one person during the day. On average, this figure is usually about 150-200 liters.

3 – the number of days it takes to settle wastewater in a septic tank

1.2 – a special coefficient to create an unexpected increase in the incoming volume of wastewater (guests, holidays).

When you know how, it is very easy to calculate the volume! Good luck to you.

## Bogdan

If you live in the house permanently, it is better to use not an ordinary concrete septic tank, but an autonomous sewage system. A conventional septic tank has a very low degree of purification of your waste, it will not exceed 70%. But the autonomous sewage system is more expensive, but the degree of wastewater treatment is much higher.

If there is a biological treatment plant, then the degree of wastewater treatment is higher than 96%. The treated water can be used for irrigation and will not pollute the environment.

Think carefully about whether you should install a septic tank. I recommend choosing a deep biological treatment plant or at least an inexpensive autonomous sewage system.

There are a lot of companies from which you can buy such sewers. You can find a company in your city and ask for additional advice on the price and what would you advise on a good system for your home.

## Ken

When choosing a septic tank, take into account the number of people in your family who live in the house. And also it is worth paying attention to the material from which the septic tank is made.

If you live in the house all the time, in such cases it is better to take an autonomous system or a biological sewage treatment plant. In this case, the degree of wastewater treatment will be much higher than that of a conventional septic tank.

But such systems can only be installed if people are constantly living in the house.