Septic tank or cesspit? Find the ideal solution

A quick guide to choosing the right wastewater disposal system

Septic tank, cesspit, sewage system... we often confuse these wastewater management systems or, if we’re unfamiliar with the sector, assume they’re all the same. In reality, these are quite distinct systems, each with unique features that make them more or less suitable for specific residential or industrial applications.

We don’t always stop to consider the most appropriate type of system for wastewater disposal. Yet this is a crucial issue—both in private homes and industrial settings—since it can impact key aspects of property management, including social and environmental implications.

Let’s explore the differences between septic tanks and cesspits, and determine which is the optimal solution for your specific needs.

A Brief introduction to the sewage system

The water that reaches homes, offices, and industrial facilities—clean and ready to use—comes out dirty and must be treated before being returned to circulation. “Wastewater,” or sewage, is water used in human activity that, after use, contains organic and inorganic substances that can harm both human health and the environment.

People often think that wastewater disposal always ends up in the “sewer.” However, the sewer system is actually a specific, well-defined infrastructure known as the “urban and wastewater drainage system.” Typically, there are two types:

• Storm sewers (white sewers), which collect water not considered hazardous to human health, such as water from industrial cooling processes, street cleaning, and rainwater runoff from streets, courtyards, and roofs.
   
• Sanitary sewers (black sewers), which collect sewage and wastewater from households and businesses that require special treatment for disposal.
   

Wastewater cannot be discharged directly into the environment (soil, rivers, lakes, or seas) without first undergoing purification, as regulated by strict Italian and European laws. These regulations define the actions needed to achieve or maintain a good quality status of surface and groundwater, protecting them from pollution.

But where does the sewage system lead? It connects to a treatment plant, typically located near major urban centers. Individual sewers connect to collectors that form the core of the urban network. These collectors, in turn, lead to a final outfall reaching the treatment facility.

Sewers are thus the most widespread infrastructure for managing urban wastewater. But what happens outside the city, or in special conditions? That’s where cesspits and septic tanks come into play. Let’s take a closer look.

How a cesspit works

In remote areas—like countryside homes, mountain cabins, or hillside residences—there is often no connection to the municipal sewage system.

In such cases, a cesspit is typically installed underground. A cesspit is essentially a buried tank where black water and waste materials from a home or residential complex are temporarily stored.

A cesspit is a standalone system, disconnected from the sewer network. This means it needs to be emptied periodically, usually by a vacuum pump that extracts the contents. How often this needs to happen depends on:

• the tank's capacity
   
• the level of usage
   
• the number of people using the connected facilities (whether living or working there)
   

The septic tank: how it works and who it's for

A septic tank works quite differently. As we’ve seen, a cesspit is a sealed, isolated system with only an inlet pipe to collect waste.

In contrast, septic tanks allow for overflow discharge through an outlet on the opposite side of the inlet. This means that wastewater can flow out without always needing to be pumped out.

Septic tanks also have an outlet pipe that channels the effluent to a final destination, typically a secondary treatment system, such as subsurface infiltration or constructed wetlands.

You’ll commonly find septic tanks in apartment buildings or groups of homes in remote areas, far from standard urban sewage networks.

Septic tank or cesspit: which one to choose?

So, there are important differences between sewage systems, cesspits, and septic tanks. Each serves a specific function. Cesspits and septic tanks, in particular, have distinct characteristics that make them more or less suitable depending on the situation.

There’s no one-size-fits-all solution, but we can certainly identify the best option for each individual case.

A cesspit is ideal for buildings located far from the municipal sewage grid—typically standalone homes. In these scenarios, connecting to the urban network would be prohibitively expensive and inefficient for a single villa or small residential complex. It’s the residents’ responsibility to call in cleaning services to regularly empty the cesspit. Keep in mind that there’s no standard size—it depends on several factors, especially the number of people using the system.

The septic tank, on the other hand, is an excellent solution for larger installations, such as buildings or homes located in small villages or settlements far from big cities.

Wastewater treatment plants by IDRO Group

IDRO Group is a leading provider of civil and industrial wastewater treatment solutions.

Whether for private homes, large commercial facilities, or industrial plants, IDRO Group leverages decades of experience to recommend the most effective solution for wastewater management.

They handle everything from system design to construction and installation—tailored to specific needs in wastewater disposal, purification, and even reuse.

Want to know the best solution for your needs? Don’t hesitate to contact us.