How Much Does a Septic Tank Installation Cost?

What Goes Into 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.

Types of Septic Tanks and What They Cost

Your chosen type of septic tank will depend on your available space, climate, house size, and soil type. Below is an overview of each septic tank system and estimated costs.

Septic System Type	Average 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

_{Note: The cost data featured in this guide was sourced using pricing estimates from Angi, unless otherwise noted.}

Anaerobic Septic Systems

Understanding septic system types is important when 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 septic systems exist, each designed to address specific site conditions such as poor soil drainage, limited space, or environmental regulations. These systems typically provide additional wastewater treatment before releasing effluent into the drain field. While they can solve installation challenges, they are generally more expensive than conventional septic systems.

For example, some advanced septic systems include treatment components that reduce pollutants before wastewater enters the soil. In the This Old House episode “How a Septic System Is Installed,” septic designer Rick Pezza explains that these systems can achieve “about an 80% reduction in nitrogen” compared with conventional septic systems. Because of the additional equipment and treatment stages involved, these systems often have higher installation costs.

Below is an overview of the different types of alternative septic systems available, along with their typical installation costs listed in the chart above:

Aerobic systems: Aerobic systems pump oxygen into the treatment tank to help bacteria break down waste more efficiently. These systems are often used on properties where additional wastewater treatment is needed before the effluent enters the drain field.
Chambered septic systems: Chambered systems replace traditional gravel or stone drain fields with plastic chambers that allow wastewater to flow and filter through the soil. They are often installed in areas with high groundwater tables or where gravel is difficult to obtain.
Constructed wetland systems: Constructed wetland systems mimic the natural filtration process found in wetlands. Wastewater passes through a treatment area filled with plants, bacteria, and microbes that help break down contaminants before the water enters the drain field.
Drip distribution systems: Drip systems distribute wastewater slowly through long lengths of tubing placed just below the soil surface. These systems are typically used on properties where a standard drain field would not provide even wastewater distribution.
Evapotranspiration systems: These systems use a large open-air tank to allow wastewater to evaporate naturally. Evapotranspiration systems work best in warm, dry climates that receive abundant sunlight.
Mound systems: Mound systems use raised sand mounds to filter wastewater when natural soil drainage is poor, or the water table is too high for a traditional drain field. Because they require additional materials and pumps, they are often more expensive to install.
Sand filter systems: Sand filter systems use layers of sand to filter wastewater after it leaves the septic tank. They are commonly installed in environmentally sensitive areas or locations near bodies of water where additional filtration is needed.

Septic Tank Material and Size Costs

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 the most common option because they are durable and resistant to damage from surrounding soil pressure. Their weight helps keep them stable underground. Concrete tanks typically cost $700–$2,000, depending on size.
Fiberglass: Fiberglass septic tanks are lightweight and corrosion-resistant, making them easier to transport and install. However, they may require anchoring in areas with high groundwater levels to prevent shifting. Fiberglass tanks usually cost $1,200–$2,000.
Plastic: Plastic septic tanks are a cost-effective option and are easy to install due to their lighter weight. However, they may be more vulnerable to cracking if the soil shifts or if the installation isn’t done properly. Plastic tanks generally cost $500–$2,500.

If you live in an older home, you may have a steel septic tank. Although steel is considered durable, steel tanks are not used in newer installations because they are prone to rusting over time. These tanks should be replaced with a newer option when they deteriorate.

Cost of Septic Tanks 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 a 500-gallon tank, which could cost as little as $500. See the chart below for more in-depth information.

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

Additional Costs When Installing a Septic Tank

Additional cost factors, like labor rates, permits, soil testing, and ongoing maintenance, can also impact your investment in a new septic system.

Labor Costs

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.

Percolation Tests

Before installing a septic system, contractors must conduct a percolation test to determine how quickly water drains through the soil. The results help engineers design a septic system that safely disperses wastewater into the surrounding ground and meets local health and environmental regulations. Pezza says this step is critical to the planning process, noting that “to determine if you can even have a septic system, it starts with a perk test.”

Depending on the property’s size and soil conditions, a percolation test typically costs $700–$2,000. Contractors usually dig several test holes in the proposed leach field area to examine soil layers and measure drainage rates before finalizing the septic system design.

Permits

To build a septic tank on your land, you’ll need to obtain a permit. Permit pricing varies from state to state, but they usually cost $450–$2,300, depending on the jurisdiction.

Maintenance

Regular maintenance helps prevent solids from accumulating in the tank and damaging the drain field. The U.S. Environmental Protection Agency (EPA) recommends having septic systems inspected and pumped periodically, depending on household use and tank size. Pumping a septic tank costs $300–$600 on average.

How Do Site Conditions Affect Septic Tank Installation?

Your property’s physical characteristics play a major role in determining the type of septic system you can have installed and the overall cost. Your property’s soil composition, groundwater levels, and available space influence how wastewater can safely disperse into the surrounding environment.

Soil drainage: Soil must allow wastewater to filter through it properly. Sandy or gravelly soils typically drain well, while clay-heavy soil may require alternative septic systems or larger drain fields.
Groundwater levels: Areas with high groundwater tables may require mound systems or other specialized designs to prevent wastewater from contaminating nearby water sources.
Lot size: Smaller properties may not have enough space for a conventional drain field, which can increase installation costs if alternative systems are needed.
Slope: Steeply sloped properties can complicate excavation and drainage design, potentially increasing labor and system costs.
Environmental regulations: Local health departments often regulate septic system placement, drain field size, and setback distances from wells, property lines, and bodies of water.

Pro Tip

Homes located in environmentally sensitive areas, like those near lakes, rivers, or coastal waters, may require specialized septic systems designed to reduce pollutants before wastewater enters groundwater, says Pezza.

DIY vs. Professional Septic Tank Installation

Septic tank installation is a complex job, and we don’t recommend 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

To ensure septic tank installation goes smoothly, here are a few tips to keep in mind.

Gather multiple estimates. 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.
Test the soil and obtain a permit. Before installing a septic tank, you’re legally obligated to test the soil using 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.*
Plan for excavation. 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.

Pro Tip

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 any land you want to use for residential purposes.

Our Conclusion

Septic tank installation costs vary widely depending on your home’s size, the type of system required, and site conditions such as soil drainage and available space. Although installation can be expensive, a properly designed septic system can safely manage household wastewater for decades. Working with a licensed installer and planning for inspections and maintenance can help protect your investment.

FAQs About Septic Tank Installation Costs

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 costs $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.