How Much Does an Engineered Septic System Cost?

Bry'Ana Arvie
Written by Bry'Ana Arvie
Updated January 20, 2022
septic tank pictured in a back yard
Photo: senssnow/ Adobe Stock


  • An engineered septic systems cost $7,000 to $20,000 on average

  • Labor fees take up 50% to 70% of the total cost

  • The most common types of engineered systems are mound, recirculating sand filter, and aerobic

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When your land couldn’t perk and failed the test, you’ll need an engineered septic system to take care of all your septic needs. The average cost to install an engineered septic system is $15,000. But factors like site prep, excavation, and location can cause the final price to cost anywhere from $7,000 to $20,000.

How Much Does an Engineered Septic System Cost Near You?

Labor costs play a significant role in how much you’ll spend on an engineered septic system. Because engineered septic systems require a different installation process than conventional ones, you’ll pay more for the time, experience, and skills required for a proper installation. So, if you stay in an area where the ground is too permeable, isn’t permeable enough, or your home resides on a hill, it’ll take longer to install with labor fees of  $45 to $200 per hour.

Engineered Septic System Cost By Type

The most common engineered septic systems are mound, recirculating sand filter, and aerobic. Below, we’ll cover each one and the actual cost of these types. 

Mound System

A mound system is one of the most common engineered septic systems for areas with high water tables, shallow solid depths, or shallow bedrocks. It uses an elevated mound of sand as the drain field. The septic tank pumps the effluent into the drain field in doses. From there, it’s filtered through the sand and dispersed into the native topsoil. Because of the labor, material such as sand and gravel, and pump tank required to install this system, homeowners pay $10,000 to $20,000 on average

Recirculating Sand Filter System

Sand filter septic systems are essentially a large PVC-line or concrete box filled with sand. A pump pushes the effluent through the top layer of sand, where the system treats and filters the wastewater. After treatment, the system disperses the wastewater through the drain field. The pump tank, excavation, installation work needed, and material used cause this system to run $7,000 to $18,000

Aerobic System

The oxygen inside the Aerobic Treatment Unit (ATU) accelerates the bacteria activity, allowing the waste to break down efficiently. Aerobic systems might also require pre- and post-treatment tanks to kill bacteria further before it’s dispersed into the drain field. The equipment and labor necessary for it bump the cost $10,000 to $20,000.

Engineered Septic System Cost Breakdown

The cost of engineered septic systems is primarily—50% through 70%—from labor costs. 

Engineered septic system labor costs account for 70% of the total project cost


worker pumping out septic tank in yard
Photo: vintagepix/ Adobe Stock

When you hire a licensed, insured, and bonded plumber, you’ll pay $45 to $200 per hour in labor cost. When plumbers install an engineered septic system, you’re typically paying for the time it takes to excavate your yard, prep the site, build the drain field, get permits, and install the system. 

However, depending on your contractor or septic tank company, you could pay a flat fee for some or all of those services. Here are the prices you can expect:

  • Land prep: $1,600-$8,000

  • Excavation: $1,200-$4,500

  • Perc test: 

Ask your contractor to provide a line-by-line written estimate to avoid any surprise bills.  

Drain or Leach Field

A drain field, also known as a leach field, is a major component of your entire septic system responsible for dispersing your filtered wastewater into the soil. The cost to build a drain field is $3,000 to $15,000.  

Engineer Fees

When you need an engineered septic system, it’s not a plumber that’ll design your new septic system but a civil engineer or soil scientist. And because they’ll need to design and potentially oversee your system’s design, expect to pay $500 to $1,000 or 5% to 15% of the project’s design budget


Each engineered system will be structured differently to fit your individual septic needs. But the materials commonly used for them include a septic and pump tank and piping. Some systems such as mounds and sand filters also require sand that costs $15 to $20 per cubic yard and gravel that costs $15 to $75 per yard


Installing an engineered septic tank will require a permit to ensure it complies with your local and state building code requirements. The cost of getting a permit is $400 to $2,000; however, the actual cost varies by city and state.

FAQs About Engineered Septic Systems

1. How long does it take to install an engineered septic system?

While it depends on your exact system and how much excavating and prepping is required, it can take seven days on average. 

2. Can I install an engineered septic system myself?

The short answer is no; engineered septic system installation isn’t a DIY project. The prospect of saving on labor costs isn’t worth the damages from an improper septic system installation. Also, these systems require an engineer to create a design and potentially oversee the installation. 

3. How long do engineered septic systems last?

Many variables, such as home size, type of engineered system, the material used, soil conditions, and water usage, dictate how long your system will last. On average, most homeowners find that their system lasts 15 to 20 years, though it’s not unheard of for them to last up to 40 years with annual and preventative septic maintenance.  

4. How much space do you need to reserve for a septic system?

You’ll need to reserve approximately 900 square feet for a three-bedroom home’s engineered septic system. However, the type of soil you have, soil absorption rate, the size of your home, climate, and local zoning code will impact the actual amount of space you need.

5. How to know if I need an engineered septic tank system vs. a conventional system?

You’ll need an engineered system if your land fails the perc test, which usually indicates the soil or groundwater conditions are not ideal for a conventional system. They can also be required when the field is located uphill from home.

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