An engineered septic line costs $15,000 on average, depending on the type, prep, and labor. Most spend between $7,000 and $20,000.
Installing an engineered septic system costs between $7,000 and $20,000, with an average project cost of $15,000. Factors like site prep, excavation, and location can cause the final price to creep up to $25,000 in some cases. Explore the different factors that impact the average cost of engineered septic systems below.
The cost of engineered septic systems is primarily—50% through 70%—from labor costs.
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: $750–$1,850
Ask your contractor to provide a line-by-line written estimate to avoid any surprise bills.
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.
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.
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.
The most common engineered septic systems are mound, recirculating sand filter, and aerobic. Below, we’ll cover the actual cost of these types.
| Septic System Type | Description | Average Cost |
|---|---|---|
| Mound system | Good for areas with high water tables, shallow soil depth, or shallow bedrock | $10,000–$20,000 |
| Sand filter system | Good for properties with not enough soil for a traditional system | $7,000–$18,000 |
| Aerobic system | Good for areas not suited for septic fields | $10,000–$20,000 |
Installing an engineered septic system is a complex and highly regulated process that requires professional expertise. Local regulations, soil assessments, and specific engineering requirements must be considered.
Attempting a DIY installation without the necessary knowledge and permits can result in costly mistakes, environmental damage, and legal issues. You should hire a licensed septic tank company near you with experience in designing and installing engineered septic systems to ensure compliance with regulations and the proper functioning of your septic system.
While the prospect of DIY septic system installation may not be feasible for properties that need engineered septic systems, we still have several cost-saving tips for you to undertake independently. After partnering with a reputable installation company, collaborate with them to pinpoint which of the following tasks you can tackle yourself:
Soil testing, which costs $1,400 on average
Obtaining building permits, which costs $50 to $500 for septic systems
Landscape prep, which starts at $1,200 on average
Managing septic tank maintenance expenses is vital, as it can range from $280 to $550 on average per year and can be over $1,000 for larger systems. To ensure you minimize these costs and keep your septic system running smoothly, consider the following guidelines:
Annual septic system inspections cost $200 to $250.
Bacteria additives cost $40 per year.
Septic tank pumping costs between $250 and $550.
Cleaning and replacing an effluent filter costs $150.
Installing an effluent filter on an existing system ranges from $275 to $850.
Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We extensively research project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We rely on reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.
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The installation timeline for an engineered septic system can vary widely depending on factors like system complexity, site conditions, and local regulations. On average, a straightforward installation may take approximately one to two weeks. This includes tasks such as excavation, tank placement, plumbing, and drain field installation. However, more complex systems or challenging terrain may extend the installation time to several weeks or even months. Proper planning and adherence to local permitting and inspection processes are crucial to ensure a timely and successful installation.
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.
Ensuring you have adequate space for your engineered septic system is crucial. You’ll need to reserve approximately 900 square feet for a three-bedroom home’s 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.
Deciding between an engineered septic system and a conventional one depends on property size, soil quality, local regulations, and environmental factors. If your property has limited space, poor soil, or is close to sensitive environmental features, an engineered system may be required. Professional site evaluations, considering water usage, long-term plans, and budget constraints, can help determine the appropriate choice. Consulting with a septic system professional is crucial for ensuring compliance with regulations and selecting the best system for your property's unique needs.
