What Are the Different Types of Septic Tanks?

There's no such thing as a "best" septic tank. What's best for you will depend on your property: your type of soil, how much space you have available, and where your water table is. There are four basic types of septic tank material: concrete, steel, plastic, and fiberglass. But it doesn't just stop there.

Now, the system responsible for the transfer of wastewater, which leaves your tank and proceeds to the ground, counts as well. Select the wrong model depending on your land, and you would be faced with either premature failures, costly repairs, or failure to pass inspections. In this walkthrough, you will discover what actually works.

Types of Septic Tanks Based on Material

1. Concrete Septic Tanks

Concrete septic tanks are made of reinforced concrete and are precast as well as field erected. Concrete septics are usually found in fixed houses where the septic tank is likely to remain in operation for a period of several years. Concrete septic tanks will be erected in areas with solid soil and where access is easy.

Pros

• Concrete is quite strong. It retains shape below the surface.
• The weight works to prevent the tank from floating due to the rise of the groundwater levels.
• These tanks will last for decades when installed properly.

Cons

• Concrete may develop cracks, particularly if the soil moves.
• It takes more effort in installation since it is heavy.
• Smaller cracks may initiate leaks, which are not easily detected at an early stage.

Most suitable for: Permanent dwellings with steady soil conditions and enough space.

2. Steel Septic Tanks

Steel septic tanks were very common years ago since they are strong and fairly easy to install. They were considered at that time as a solid alternative to concrete.

Pros

• When new, steel in the tank is strong.
• It could handle the pressure of soil in the initial years.

Cons

• Steel rusts when it is exposed to wastewater and moisture.
• As time passes, the rust weakens the tank and can even cause it to spring holes or collapse.
• The overall life is considerably shorter than other types of tanks.

Why most professionals no longer recommend them: As steel corrodes, the risk of failure increases. As a result of this, many professionals shy away from steel tanks: some areas even forbid their use anymore.

3. Plastic (Polyethylene) Septic Tanks

Plastic septic tanks are made from molded polyethylene materials. They are much lighter compared to concrete or steel materials, which makes them easy to transport and install.

Pros

• It does not rust or corrode.
• Its lightweight designs ensure fast installation.
• It makes joints leak less due to its single-piece design.

Cons

• Since they can be so lightweight, they can actually float if there is an increase in the water levels of the ground where the tank has been placed without tying down the tank
• Ineffective backfill work may result in the displacement and bent tank.
• However, they are not as strong as concrete and fiberglass tanks.

Best for: Small homes and areas where installability is closely monitored.

4. Fiberglass Septic Tanks

Fiberglass septic tanks are more robust compared to plastic septic tanks but are lighter compared to concrete septic tanks. They are a solid piece and are mostly preferred when the soil is less favorable.

Pros

• Fiberglass does not rust or decompose in wastewater.
• More durable than plastic but portable nonetheless.
• Less prone to cracking compared to concrete.

Cons

• It costs more than plastic tanks.
• Requires careful mounting to prevent unequal pressure.
• Incorrect backfilling can also cause problems.

Best used for: Properties with problematic soil or areas where heavy equipment cannot easily gain access.

Types of Septic Systems (Beyond the Tank Itself)

1. Conventional Gravity Septic System

This is the most common septic system. The septic tank receives wastewater from the residence. Solids settle at the bottom. Liquids move out into a drainfield, where the soil helps filter the water.

Where it works best

• Properties with good soil drainage
• Sites with enough open land for a drainfield
• Areas with a low water table

Limitations

• Does not work well in poorly draining soil
• Needs enough space for the drainfield
• Can fail if the soil becomes compacted or saturated

2. Aerobic Treatment Units (ATUs)

Aerobic systems add oxygen to help break down waste faster. This extra treatment produces cleaner wastewater before it reaches the drainfield.

Where they are used

• Areas with poor soil conditions
• Properties with high groundwater levels
• Sites where local rules require higher treatment

Limitations

• Requires electricity to operate
• Needs regular maintenance and inspections
• Operating costs are higher than basic systems

3. Chamber Septic Systems

Instead of gravel, these systems use plastic chambers in the drainfield. The chambers hold wastewater and allow it to spread evenly into the soil.

Where they work well

• Sites where gravel is hard to source
• Soils that can absorb water but need better distribution
• Areas needing quicker installation

Limitations

• Not suitable for all soil types
• Limited availability in some regions
• Still needs proper soil absorption to function well

4. Mound Septic Systems

A mound system places the drainfield above ground level. Wastewater is pumped from the tank into the raised mound, where it filters through sand and soil.

Where they are used

• High water table areas
• Shallow soil conditions
• Locations where traditional drainfields are not possible

Limitations

• Higher installation cost
• Requires a pump and electricity
• The mound is visible and takes up yard space

5. Drip Distribution Systems

This system sends treated wastewater through small drip lines placed just below the soil surface. The water is released slowly over a wide area.

Where they work best

• Properties with limited space
• Uneven or sloped land
• Areas needing precise water control

Limitations

• Requires filtration to prevent clogging
• Needs regular maintenance
• Higher system complexity

How to Choose the Right Septic Tank for Your Property

The right septic tank depends less on preference and more on what your property allows. Before comparing materials or systems, focus on the limits and demands of your site.

• Check your soil type first. If your soil drains well, a standard gravity system works. If it drains slowly, you will need a system that treats wastewater more before it reaches the ground.
• Know your water table level. A high water table limits your options. In these cases, mound systems, aerobic systems, or drip distribution systems are often required.
• Measure available space. Traditional drainfields need more land. Smaller or uneven lots usually need compact systems that spread wastewater more efficiently.
• Think about daily water use. Larger households create more flow. Your tank and system must handle steady use without overload.
• Decide how much maintenance you can handle. Systems with pumps and electricity need regular servicing. Simpler systems need less attention but require better site conditions.
• Confirm local rules early. Many areas restrict which systems you can install. In some cases, the choice is already made by regulation.

When your system matches your soil, space, and usage, it lasts longer and fails less often. A soil test and local approval should always come before the final decision.

Conclusion 

The right septic tank depends on your property and household use. Choose a system that fits your soil, space, and water table, and make sure it can handle your daily flow. Check local regulations and run a soil test before installation.

Once your system is installed, keep it working efficiently with regular care. One simple step is using a septic tank cleaner like BioClean septic tank cleaning powder. It helps maintain bacteria that break down waste, reduces buildup, and keeps your tank running smoothly. Adding this to your routine can prevent blockages and extend the life of your system.