How Much Does a Septic System or Tank Cost?

Labor Cost to Install a Septic System

Labor makes up 50% to 70% of your total project cost. In a typical installation, labor is more expensive than the price of the tank itself. Whereas the tank size needed for a three- to four-bedroom home may cost $900 to $1,500, the cost to install can range from $1,500 to $4,000.

Septic Tank Cost by Size

How much you'll pay for a septic tank depends on the size. Larger homes require a larger tank that can meet the demands of a bigger household.

Anaerobic vs. Aerobic Septic Tanks 

Anaerobic septic tanks are traditional systems where anaerobic (non-oxygen consuming) bacteria digest the solid waste. Once turned into wastewater, the waste exits the tank and goes to a large leach field where oxygen-loving bacteria get to work breaking down the waste. As the wastewater penetrates the soil, the bacteria kill off potentially harmful organisms.

Aerobic systems are more complex and often include a composting toilet and a continuous flow system. This septic system is more expensive than the traditional anaerobic type but is more efficient. Because the effluent (or the sewage or wastewater) is of higher quality, these systems require a smaller leach field. Read more about the two system types below.

Anaerobic Septic System

The classic anaerobic system installed costs $3,000 to $8,000 on average. Anaerobic systems are typically more inexpensive to install than the more complex aerobic system, but they're not as efficient at cleaning the tank, so you'll need a larger leach field to pick up the extra workload.

An anaerobic septic system is a relatively simple system consisting of a pipe leading from the house to the tank and a branched pipe leading from there to the drain field. These systems rely on anaerobic bacteria (bacteria that don't use oxygen) to break down waste in the tank before further bacterial processing in the soil.

Aerobic Septic System 

Aerobic systems cost $10,000 to $20,000 on average. You'll likely need a second tank if you're converting from anaerobic to aerobic, but it'll only cost $5,000 to $10,000 to convert. Aerobic systems break down waste more effectively in the tank than anaerobic systems, meaning you can often use a smaller drain field, which is great for smaller properties.

An aerobic system is a wastewater system that relies upon aerobic bacteria (oxygen-loving bacteria) to break down waste in the tank. You'll need an aerator and an electrical circuit running to the system, and with small, mounded, or specialty fields, you may also need a dose or pump tank to push the effluent uphill or out in doses.

Alternative Septic System Costs

You’ll want an alternative septic system when you have a small property, high water table, high bedrock, bad soil, or simply want to use less space.

Chambered System

Chambered systems cost $5,000 to $12,000 to install. They use plastic perforated chambers around pipes often set in sand, eliminating the need for gravel. They're quick and easy to install but more susceptible to crushing forces, like vehicles.

Built Wetland System

Built wetland systems cost $8,000 to $15,000 to install and more if you use an aerobic tank. They mimic the natural cleansing process found in wetlands and are treated by microbes, plants, and bacteria in a wetland tank before passing to the soil. The waste also supports the wetland plants and microbe population.

Recirculating Sand Filter Septic System 

Sand filter septic systems cost $7,000 to $18,000 to install. They're constructed either above- or below-ground and use a pump chamber to push the wastewater through a sand filter prior to dispersal in the ground. The filter box typically has a PVC lining, and the pump pushes the effluent through the sand and back to the pump tank, where it's then dispersed through the ground.

Evapotranspiration System

Evapotranspiration systems cost $10,000 to $15,000 to install. They use a unique drain field setup that allows the liquid to evaporate from the top of an open-air tank and are only useful in dry, arid climates that see little rain or snow.

Drip Septic System 

Drip systems cost $8,000 to $18,000 to install. They work like other systems, except they use extensive drip tubing and a dosing system. They release smaller timed doses, which work well in shallow soil depths. But a drip system costs more than a traditional system since it requires a dose tank, pump, and electricity.

Mound Septic System 

A mound septic system costs $10,000 to $20,000 to install. It’s the most expensive system but often necessary in areas with high water tables, shallow soil depth, or shallow bedrock. It relies upon an elevated sand mound for the drain field rather than excavating into the soil. Its increased expense comes from both the added machinery needed to pump effluent uphill into the mound and the materials and creation of the mound itself.

Septic Tank Costs by Material

The type of septic tank you choose will cost between $500 and $14,000, depending on the use, material, and size. You'll rarely spend more than $3,000 on the tank itself for most residential settings. Most large, higher-priced units are designed for apartments or community septic systems.

Concrete 

Concrete tanks cost $700 to $2,000, and total installation costs run $2,300 to $6,500. They’re one of the most common types installed and usually durable for a couple of decades because they’re susceptible to cracking or separation. It's important to have it manually inspected regularly against cracks and runoff. Inspections and regular cleanings help prolong its life span. Your pro can tell you how often to have it inspected, but it’s usually anywhere from one to three years.

Plastic and Poly

Plastic septic tanks cost $500 to $2,500 on average, not including installation. Plastic is a durable, lightweight, and relatively inexpensive material, and it rarely cracks like concrete and doesn't rust. However, plastic can be vulnerable to damage during installation because it’s so lightweight.

Fiberglass 

Fiberglass septic tanks cost $1,200 to $2,000 on average, not including installation. Fiberglass doesn't crack easily or rust, but it's susceptible to damage during installation, like plastic. Also, the lower weight makes it more susceptible to structural damage, and the tanks themselves can shift in the soil.

Steel

You'll likely never see a new steel tank installed. Regardless of how well-made one is, it'll eventually rust or corrode. Many local building codes don't allow them anymore, and you'll often only see them in existing installations. Steel isn't durable in the ground, and it's the least popular septic tank type.

Leach Field Installation Costs

A leach or drain field is the section of the septic system that transports the wastewater back to the soil and costs anywhere from $5,000 to $20,000 to install. The first sign of a problem with the drain field is often a swampy area in the yard or sewage odor on the property. A drain field replacement can cost anywhere from $10,000 to $50,000, depending on how much remediation you need for clogged or flooded fields.

Septic Tank Installation Add-On Costs

Besides the tank and leach field, you'll have a few other fees you'll need to consider in your budget. You may have some of these included in your overall project price, so ask for line-item costs on your estimate.

• Land excavation costs: $1,500–$5,600

• Cost of building permits: $450–$2,300

• Perc test cost: $750–$1,900

• Riser installation: $300–$600

• Sewer pipe cost: $100–$240 per linear foot

• Septic distribution box: $50–$650

Septic Tank Replacement Cost

At around $3,000 to $10,000, replacing the tank is considerably less costly than installing a completely new system because there are no excavation costs. If you do need to replace the whole tank, there are some costs you need to be aware of. For example, you'll need to have the tank pumped and cleaned first to eliminate any remaining waste. Pumping a septic tank costs an average of $420, and cleaning afterward costs an additional $100 to $800, depending on the tank size.

When the system begins to fail, it may crack or corrode, causing the waste to leach into the groundwater. When this happens, the well water may become contaminated, the yard may turn swampy, and the septic system may stop functioning. Here's a rundown of specific septic tank parts and their average prices:

• Septic tank pump replacement: $800–$1,400

• Baffle replacement: $300–$500 

• Filter replacement: $230–$280

• Tank lid replacement: $30–$70

• Drain field replacement: $7,000

When replacing your system, consult with your service pro about the pros, cons, and costs of upgrading to a more efficient aerobic system.

DIY vs. Hiring a Septic System Pro

Septic system installation is a complicated process. An improperly installed unit can lead to water pollution, damage to the home, and expensive repairs. In addition, an unpermitted installation can make a home difficult to sell and insure. Be sure to interview at least three pros before choosing someone. For estimates on your project, contact a local septic tank installer today.