How Much Does a Septic Tank Installation Cost?
Typical Cost Range: $2,000 – $15,000
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If you home isn’t connected to a municipal sewer system, your septic tank performs the essential task of treating wastewater and returning it to the earth. Septic systems are relatively common, and homeowners have a range of options to choose from. Unfortunately, installing or replacing a septic tank can be expensive. The national average for septic tank installation ranges from $3,480–$11,625 but can reach above $23,000 on the high end.*
This article covers the types of septic systems available to homeowners, their costs, and the best ways to prepare for an installation.
*Cost data sourced from contractor estimates used by Angi, as updated in September 2023.
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What Is a Septic Tank?
A septic tank is an underground chamber made of concrete, fiberglass, or plastic that serves as the primary treatment component for wastewater (sewage) in homes and small businesses not connected to a municipal sewer system. It works through a combination of settling and natural bacterial digestion to break down solids and organic matter present in the wastewater.
A conventional septic system uses gravity to move household sewage into the septic tank. Sewage is separated into layers, with solid waste settling at the bottom and liquid sewage rising to the top. Naturally occurring bacteria in the tank break down the organic matter.
When liquid sewage rises to the level of the outflow pipe, the partially treated liquid waste (known as effluent) flows into the drain field. Perforated pipes allow the effluent to slowly seep into the surrounding soil, where it decomposes further. The soil helps prevent contamination by filtering the wastewater before it eventually returns to the water table.
Factors Affecting Septic Tank Installation Costs
The average price for a septic tank installation falls around $7,500. Final costs vary greatly based on home size and other key factors outlined below.
- Tank type: A complicated or cutting-edge system will cost more money than simpler options. Some types of septic systems require a large amount of operating space, which increases your installation costs.
- Tank material: Investing in more durable materials increases your project costs but results in a longer-lasting system.
- Tank size: Your septic tank’s size must match your home’s size. Bigger homes require larger tanks to provide adequate drainage.
- Labor: Complex septic tank systems come with additional installation fees and labor costs. Labor costs vary by region but typically account for 50–70% of the total cost.
Septic Tank Installation Costs by Type
Your chosen type of septic tank will depend on your available space, climate, house size, and soil types. Below is an overview of each septic tank system and estimated costs.
Septic Tank Costs by Type
| System Type | Cost |
|---|---|
|
Aerobic |
$10,000–$20,000 |
|
Anaerobic |
$3,000–$8,000 |
|
Chambered |
$5,000–$12,000 |
|
Constructed wetland |
$5,000–$12,000 |
|
Drip distribution |
$8,000–$18,000 |
|
Evapotranspiration |
$10,000–$15,000 |
|
Mound |
$10,000–$20,000 |
|
Sand filter |
$7,000–$18,000 |
Anaerobic Septic Systems
Understanding septic system types is important when looking at installing a septic tank. Traditional septic systems use anaerobic bacteria to break down waste in the septic tank. These systems don’t require additional chemicals or power and are an affordable option for homeowners. However, anaerobic systems don’t clean the tank and require a larger drain field to work correctly.
If you have the space to accommodate a large drain field, an anaerobic system could be a viable option for your property. These systems are cheaper to install than aerobic systems, costing $3,000–$8,000 on average.
Alternative Septic Systems
Several alternatives to traditional anaerobic systems exist, each with its own benefits. Many are designed to address specific challenges, such as poor soil quality, less available space, and the need to release cleaner wastewater. However, these benefits generally come at a higher cost.
Here’s an overview of the different types of alternative septic systems are available, which we have listed the cost ranges for in the chart above:
- Aerobic systems: By pumping oxygen into the treatment tank, these systems generate naturally occurring bacteria to process the waste.
- Chambered septic systems: Replacing the need for a gravel/stone system, chambered systems use gravel-less drain fields with leaching chambers for filtration. They are ideal in areas with high groundwater tables or limited gravel.
- Constructed wetland septic systems: Similar to the natural process in real wetlands,
these systems cleanse wastewater using bacteria, microbes, and plants. The waste then helps those plants to thrive. This design is the most eco-friendly septic system available. - Drip distribution septic system: Drip systems are made to “irrigate” septic water over a larger area using long lengths of tubing throughout the leach field. Homeowners will need ample space and power for this type of system.
- Evapotranspiration septic system: These systems use a large open-air tank to allow the effluent to evaporate naturally. This type of system works best in climates that receive abundant sunlight and heat.
- Mound septic system: Mound systems use mounds of sand to clean wastewater instead of a typical leaching field. These systems require the installation of sand and a pump tank.
- Sand filter system: This septic system uses sand to filter effluent after leaving the pump tank. The treated water then flows to the drain field. Sand filter septic systems work best in areas near bodies of water or with a high water table.
To learn more about how traditional anaerobic systems work and why you might need to upgrade to a newer design, check out the video below. Engineer Jeff Balch explains the new space-saving sand filter system he plans to install:
Cost of Septic Tank Materials
Material costs impact the final price of your septic tank. More durable materials have a longer life span but a higher price tag. Below are the most common material types available for your home:
- Concrete: Concrete septic tanks are durable and rust-proof but are hard to repair if damaged. Depending on the size, concrete tanks may cost around $700–$2,000.
- Fiberglass: Fiberglass septic tanks are stronger than their plastic counterparts but can be shifted or displaced if the water table rises too high. These tanks are priced from $1,200–$2,000.
- Plastic: Plastic septic tanks are cost-effective but prone to damage. They cost around $500–$2,500.
If you live in an older home, you may have a steel septic tank. Although steel is considered a durable material, steel tanks are not used in newer installations because they are prone to rust over time. These tanks should be replaced with a newer option when they deteriorate.
Septic Tank Cost by Material
| Material | Average Cost |
|---|---|
|
Plastic |
$500 to $2,500 |
|
Concrete |
$700 to $2,000 |
|
Fiberglass |
$1,200 to $2,000 |
Cost of Septic Tank by Size
Your septic tank size correlates with the number of bedrooms in your home. The more bedrooms your home has, the larger your septic tank must be. For example, a 1,000-gallon tank would cover a three-bedroom home and cost up to $1,500. However, a one-bedroom home would only need only a 500-gallon tank, which could cost as little as $500. See the chart below for more in-depth information.
Recommended Tank Size by House Size
| Number of Bedrooms | Recommended Tank Size (in gallons) | Cost |
|---|---|---|
|
1 bedroom |
500 |
$500–$900 |
|
2 bedroom |
750 |
$700–$1,200 |
|
3–4 bedroom |
1,000 |
$900–$1,500 |
|
5–6 bedroom |
1,200 |
$1,200–$1,600 |
|
6–7 bedroom |
1,500 |
$1,500–$2,500 |
Cost of Labor
- Labor costs must be factored into your project. Some septic system types require a large amount of space or a complex installation. Typically, you hire a plumber or other specialist to replace or install a septic tank. Depending on the project’s complexity, labor costs could fall between $1,500 and $4,000.
To get a better understanding of the labor involved, check out this video about how a septic system is installed. Rick Pezza walks This Old House expert Richard Trethewey through all the steps and components, from the tank itself to the bottomless sand filter:
Additional Septic Tank Installation Cost Considerations
Additional cost factors—such as permits, soil testing, and ongoing maintenance—impact your investment in a new septic system. We’ll cover these added costs below.
Septic Tank Component Costs
Although the average lifespan of a septic tank is about 20 to 30 years, your system will experience normal wear and tear of its components over time. Most septic tank systems have parts that are independent of each other, making it possible to replace a single component.
Below are some common septic tank components that may need to be replaced or repaired over time:
- Access risers: For septic tanks buried far into the ground, access risers bring the lid to the surface. For these replacements, expect to pay about $300–$600.
- Baffle: The baffle is essential in directing the wastewater through the septic tank for proper removal. It can be replaced for $300–$500.
- Distribution boxes: Septic distribution boxes evenly channel wastewater to the drain field. Replacing a cracked or clogged distribution box ensures proper flow, prevents system failure, and costs $500–$1,500.
- Filter: Septic filters trap solids before they reach the drain field and need to be replaced regularly to maintain efficiency and protect the system from backups. When it’s time to replace the filter, expect to pay $230–$280.
- Leach field: These are one of the most expensive replacements in a septic tank system. Homeowners can expect to pay $2,000–$10,000 to install a leach field.
- Tank lid: Lids may naturally crack over time with continued tank use. Although the replacement part costs between $30 and $70, opting for a professional installation will increase the total from $100–$300.
- Tank pump: Not all systems will require a tank pump. However, if you do need a replacement, you can expect to pay $800–$1,400.
Homeowners should also consider a septic tank warranty to cover their system when it’s time for repairs. Individual component replacements will cost much less than replacing your entire system.
DIY vs. Professional Septic Tank Installation
Septic tank installation is a complex job, and we do not recommended trying to do it yourself. You would need extensive knowledge of sewer systems and plumbing to do it properly. You would also need heavy machinery to perform the tank excavation and drain field installation.
An improper DIY septic tank installation could lead to sewer backups and groundwater contamination. Given the stakes and equipment involved, we recommend hiring a licensed septic tank installer or plumber to complete the installation.
How To Prepare for Your Septic Tank Installation
Before any excavation begins or signing any paperwork, get estimates from multiple licensed septic tank installers. Research each company using trusted third-party review sites. Ensure the contractor you select holds the proper insurance and licensing and includes necessary preparations like excavation and drain field testing in their estimate.
Before installing a septic tank, you’re legally obligated to obtain a percolation or “perc” test. This test confirms the soil meets the requirements set forth by the city and your local health department. For instance, the soil may need to have adequate amounts of permeable contents like sand or gravel. Once the land passes the percolation test, you can obtain a permit and start the installation process.
Note: If you want to put a septic tank on a piece of land, it must pass the percolation test. We recommend ordering a test before purchasing the land you want to use for residential purposes.
Heavy equipment is needed to excavate the large amount of land necessary for a septic tank. Make sure to budget for landscaping costs to fix any damage incurred during excavation.
If you’re building a new home, schedule the excavation at a time when it’ll have minimal impact on the construction process. Typically, this is before paving the driveways and sidewalks, but after the home’s main frame is built.
Our Conclusion
Whether you’re planning a new installation or replacing your current tank, septic tank costs can vary significantly based on home size, local requirements, and the type of system you choose. Although DIY septic tank installations are theoretically possible, we do not recommend them unless you have professional experience. Instead, you should consult a professional installer to complete your job. Research at least three installers in your area and compare their quotes, available equipment, labor costs, and warranty options.
FAQ About Septic Tank Installation Cost
Can I install my own septic tank?
We do not recommend that you install your own septic tank. Septic tank installation requires special equipment or expertise that most homeowners do not have.
What is the cheapest septic tank?
The cheapest option is a plastic septic tank, which typically cost $500–$2,500. These tanks are generally lighter, easier to install, and resistant to water corrosion. However, they are also more vulnerable to damage during installation.
How often should I pump my septic tank?
You should pump your septic systems every three to five years, depending on the recommendation from your installer. Septic tank pumping prevents solid waste from building up and leaking into the surrounding soil or groundwater.
How do I maintain my septic tank system?
To properly maintain your septic tank system, avoid pouring toxins, harsh chemicals, oil, or oil-based substances down your kitchen or bathroom drains. Have your septic tank inspected and pumped every three to five years. Alternative septic systems should be inspected annually.
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