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What’s the Average Cost of a Septic System?

What’s the Average Cost of a Septic System?
Jacqueline DeMarco
Jacqueline DeMarcoUpdated August 8, 2023
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Editor’s note: Lantern by SoFi seeks to provide content that is objective, independent and accurate. Writers are separate from our business operation and do not receive direct compensation from advertisers or partners. Read more about our Editorial Guidelines and How We Make Money.
A septic system is a vital component of any home that relies on it, which is why it’s not a good idea to sleep on maintenance or replacements. If someone needs a new septic system for their home or is installing one for the first time, cost is likely top of mind. On average, a septic tank costs $3,918 to install.  Learn more about what this home improvement project will cost and how to better plan for it. 

What Is a Septic System?

A septic system is a self-contained wastewater treatment system commonly used for homes in areas where there is no access to a centralized sewage system. It consists of two main components: a septic tank and a drainfield (or soil absorption field).The septic tank is responsible for breaking down organic matter and separating floatable materials and solids from the wastewater. This process allows the effluent (the liquid portion) to be separated from the solid waste.In conventional septic systems, the effluent is released from the septic tank into a series of perforated pipes buried in a designated area called the drainfield. The drainfield is designed to slowly release the effluent into the surrounding soil, where further treatment occurs as it filters through the soil.

Types of Septic Systems

The choice of septic system depends on various factors such as household size, soil type, site slope, regulations, and environmental conditions. Proper maintenance is essential to ensure the effective functioning of septic systems and prevent environmental or health hazards.Common types of septic systems include:
  • Conventional system: Consists of a septic tank and a gravel/stone drainfield for further treatment as effluent filters through the soil.
  • Chamber system: Uses connected chambers instead of gravel/stone, making it easier to construct and suitable for areas with high groundwater levels.
  • Drip distribution system: Utilizes a timed dose delivery of wastewater to the drip absorption area, requiring a large dose tank and additional components.
  • Aerobic treatment unit (ATU): Injects oxygen into the treatment tank to increase bacterial activity and provide additional nutrient treatment.
  • Mound systems: Used in areas with shallow soil depth, high groundwater, or shallow bedrock, requiring periodic maintenance and substantial space.
  • Recirculating sand filter system: Provides high nutrient treatment and works well for sites with high water tables or proximity to water bodies, but is more expensive.
  • Evapotranspiration system: Evaporates effluent into the air, suitable for arid climates with adequate heat and sunlight, but not ideal for wet conditions.
  • Constructed wetland system: Mimics natural wetland treatment processes using microbes, plants, and media to remove pathogens and nutrients.
  • Cluster/community system: Collects wastewater from multiple dwellings or buildings under common ownership, conveying it to a shared treatment and dispersal system.

How Much Does a Septic System Cost?

On average, new septic tanks cost $3,918 to install, but they can range greatly in price. Homeowners can generally expect to spend between $1,500 and $5,000 on a new septic tank. However, if the septic tank is a more complex model, prices can increase substantially. Septic system installation with two alternating pumps can cost between $9,571 and $15,000.Recommended: Guide to Getting a $5,000 Personal Loan

Factors Affecting Septic System Costs

What a homeowner’s actual septic tank replacement costs are will depend on a handful of unique factors. Let’s break those factors down. 

Septic System Complexity and Size

When designing a septic system, several factors must be considered to determine the appropriate tank capacity and leach field size. These factors include:
  • Property size: The available land area plays a crucial role in determining the size of the leach field. Larger properties can accommodate more extensive drain fields, while smaller ones may require more compact systems.
  • Expected water use: The number of occupants in the household and their water usage patterns influence the required tank capacity. More significant water use will necessitate a larger tank to handle the wastewater adequately.
  • Local building codes: Local regulations and building codes specify the minimum requirements for septic system size. Compliance with these guidelines is essential to ensure proper functioning and avoid legal issues.

Site Preparation and Excavation

Before installing a septic system, the installation area needs proper clearing and leveling. The process involves removing any vegetation, rocks, or debris from the site to create a flat surface for the system's components. This helps facilitate the installation process and ensures the system's stability. Clearing the land can cost about $950 for a quarter-acre lot if the clearing needs are minimal and the ground is flat and rock-free. 

Permitting and Regulatory Requirements

Before installing a septic system, it is essential to obtain the required permits and approvals from the local authorities. These permits ensure that the proposed septic system complies with health, environmental, and building codes to protect public health and the environment.The permitting process may involve submitting detailed plans of the proposed system, including the tank capacity, leach field size, and other components. The local health department typically reviews these plans and issues the necessary permits if the system meets the specified requirements. Typically building permits cost between $250 and $450. 

Installation Costs

The cost range for septic system installation can vary based on several factors, including property size, soil conditions, system type, and location. While the average cost of installation ranges from $4,950 to $22,950, the size of the gravel base can play a major role in pricing. 
  • 12" gravel base: $30 per linear foot.
  • 24" gravel base: $11 per linear foot.
  • 36" gravel base: $30 per linear foot.
  • Additional costs for pipe laid 6' deep: $20 per linear foot.

Maintenance and Repair Costs

Staying on top of septic tank maintenance is super important if homeowners want to keep the system working well and want to avoid more expensive repairs in the future. On average, septic tank repairs cost $600 to $3,000. That cost drops to $500 to $1,500 for minor repairs, which is why it’s important to tackle repair needs before they grow bigger. 

Financing Options and Considerations

If a homeowner can’t afford to pay cash for a new septic system or repairs, they do have a few plumbing financing options available to them. 
  • Personal loan. When someone needs financing options for covering the costs of a new septic tank, personal loans for home improvement offer flexibility and accessibility. These unsecured loans don't require homeowners to put their property at risk as collateral, and qualifying with fair credit is possible. However, personal loans typically come with shorter repayment periods, ranging from one to seven years, and higher interest rates compared to secured loans.
  • Home equity loan. Homeowners may consider home equity loans, which provide the full loan amount upfront with a fixed interest rate and a repayment period ranging from five to 30 years. Home equity loans are ideal for those planning to pay off the debt over an extended period and for one-time home improvement projects that don't require revolving a balance.
  • Home equity line of credit (HELOC). Another option is a home equity line of credit (HELOC), which offers a variable interest rate that fluctuates with market rates. The initial variable rate is typically lower than that of a home equity loan, making it beneficial for short-term repayment plans. HELOCs are suitable for homeowners with ongoing renovation projects, as they allow borrowing and repaying funds as needed, creating a revolving line of credit.

The Takeaway

Septic tanks are an expensive component of any home that relies on them to run smoothly, but they aren’t one that can be avoided. If someone can’t cover the costs of repairing or replacing a septic tank with cash, they can turn to financing options. To make finding the right type of loan and lender easier, homeowners can use Lantern. Lantern can help you compare rates and find loan offers in minutes.
Photo credit: iStock/SimplyCreativePhotography

About the Author

Jacqueline DeMarco

Jacqueline DeMarco

Jacqueline DeMarco is a personal finance writer and editor based in Southern California. While she spends the bulk of her time writing about complex financial issues, she also tackles a variety of subjects ranging from food to fashion to travel. Her work can be found across dozens of publications such as Credit Karma, LendingTree, Northwestern Mutual, The Everygirl, and Apartment Therapy.
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