What Size Residential Septic Tank Should You Install?

Choosing the Right Residential Septic Tank Sizes
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What Size Residential Septic Tank Should You Install?

As cities become more densely populated and the desire for self-sufficient living increases, many homeowners are seeking properties outside urban areas that provide a sense of independence.

One crucial element of such a lifestyle is managing your own wastewater disposal system. For numerous homes in rural and suburban areas, septic tanks provide a practical approach.

In this article, we will examine the basics of septic tanks, their significance in residential environments, the suitable dimensions for different family sizes and the benefits of choosing plastic septic tanks over their concrete counterparts.

What is a Septic Tank and Why Have One in a Residential Setting?

A septic tank serves as an underground wastewater treatment facility, primarily utilized in rural and suburban locations where centralized sewer systems are unavailable. 

Septic tanks handle and dispose of household wastewater, including sewage from toilets, sinks, showers and laundry appliances. They function by separating solids from liquids and facilitating the natural decomposition of organic matter through the bacteria found in organic waste.

Septic Tanks Contribute to Self-Sufficiency

Septic tanks offer several benefits, particularly for homeowners seeking self-sufficiency or who reside in areas without easy access to public sewage systems. The advantages include reduced costs, minimized environmental impact and the ability to manage wastewater independently. Septic systems may also appeal to potential homebuyers who prioritize self-reliance.

Determining the Appropriate Size for a Residential Septic Tank

Your local building permit department can assist you in making sure you choose the correct tank for your location and needs. These are general guidelines:

  • Three-bedroom homes should have a minimum 1,000-gallon septic tank.
  • Four-bedroom homes should have a septic tank with a capacity of 1,250 gallons or more.
  • Five-bedroom homes may require a 1,500-gallon tank.

The Benefits of Plastic Over Concrete Septic Tanks

Septic tanks are manufactured from different materials like concrete, fiberglass and plastic. Of these, plastic septic tanks provide a number of advantages over concrete.

Plastic septic tanks are typically more affordable than concrete alternatives. The price advantage is primarily due to the lighter weight, which results in lower shipping and installation costs. Moreover, plastic tanks are easier to handle and install and often require less manpower and machinery during the installation process.

Septic tanks are highly resistant to corrosion and rust to ensure that they maintain their structural integrity over an extended period. In contrast, concrete tanks are prone to cracking and leaking due to changes in the surrounding soil or groundwater conditions.

Plastic tanks necessitate less maintenance compared to concrete tanks. Their smooth internal surface prevents the buildup of solid waste materials and reduces the frequency of tank cleaning and pumping.

Tank Depot’s Plastic Septic Tanks: One or Two Compartments?

Tank Depot provides a variety of plastic septic tanks to accommodate different residential needs with both one and two-compartment options available — but what determines whether you require a one or two-compartment tank?

One-Compartment Tanks


one-compartment septic tank is a single, underground watertight chamber designed to filter raw domestic wastewater. As the heavier particles settle at the bottom of the tank, lighter materials such as grease will rise to the surface and stay there. Meanwhile, the effluent travels onward toward disposal, where it will get additional treatment before entering into drainage fields.

500 Gallon Below Ground Septic Tank


This 500-gallon below-ground septic tank is lightweight but incredibly durable. It was constructed with a seamless design and FDA-approved resin for wastewater storage.

500 Gallon Low Profile Plastic Septic Tank


The N-43522 is a low-profile one-compartment septic tank made of rotationally molded polyethylene resin with a seamless construction. Its design makes it highly durable and resistant to cracks. The tank is intended for the storage of wastewater and is low-profile and molded in one piece to reduce installation time and effort.

Two-Compartment Tanks

two-compartment septic tank consists of two separate chambers. The first chamber performs the same function as a one-compartment tank by allowing solids to settle and other matter such as oils and grease to float while partially treating the wastewater. The partially treated wastewater then flows into the second chamber, where it undergoes further treatment as additional solids settle and greases and lighter solids continue to float.

750 Gallon Norwesco Low Profile Septic Tank (Preplumbed)


The N-43521 tank has a 750-gallon capacity and is made from rotationally molded polyethylene resin that is designed to last. Its seamless construction means that it doesn’t require any additional assembly, which makes it an ideal septic solution for homes, cabins and homesteads.

1,000 Gallon Norwesco Septic Tank

A yellow, plastic, ribbed septic tank. The septic tank has two compartments on the top.


The 1,000-gallon tanks can easily be transported in a pickup truck because they are lightweight. Installing the tanks is also quick and easy, so you can start using them immediately. The tanks are made of strong polyethylene resin that can withstand soil chemicals and sewage gases without rusting or corroding. 

They are designed as a single piece to prevent leaks and have two 20-inch watertight domed lids that are stronger than other lid designs, making them a reliable choice for storing waste.

Norwesco 1,500 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)

 A low profile septic tank. The tank is green, ribbed and plastic.


The Norwesco 1,500-gallon low-profile septic tanks are easy to install because they come molded in one piece and no additional assembly is required. They are durable and seamless which eliminates any chances of leakage. 

Also, there is no need for any special backfill or water filling during installation. The tanks can be pumped dry during pump-outs and can have a cover of anywhere between 6 to 36 inches. They are versatile and can be used as a septic tank, pump tank or for storing non-potable water.

Invest in a Durable and Cost-Effective Residential Plastic Septic Tank System from Tank Depot

Tank Depot offers plastic septic tanks made by the top manufacturers in the industry. Our company has been providing high-quality tanks at the lowest prices since 1998, along with expert customer service. 
Contact us today for additional details or to locate a store in your area!

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