Septic System Cost

How Much Does a Septic System Cost?

Medium: Averages $2,000-$5,000; Runs $4,000-$12,000 in Higher Cost Areas

Enhanced System: $10,000-$20,000+

For homes that aren't connected to a municipal sewer plant, a septic is an on-site system that collects, treats and disposes of household wastewater by slowly filtering it through underground soil. Typically there are two main parts, a septic tank and a soil absorption system (also called a drainfield, leachfield or disposal field). These are located underground and connected to the house by sewage pipes.

Typical costs:

Installing/replacing a conventional septic system (including the tank) averages $2,000 -$5,000 in the Midwest, but can be $4,000 -$12,000 or more in areas where materials and labor rates are higher.
Enhanced, engineered or alternative septic systems that use mounds, sand/peat filters, aerobic systems and/or constructed wetlands can cost $10,000 -$20,000 or more, according to the Rhode Island Regional Water Quality Program.
These alternative septic systems work better than the conventional approach for sites with high groundwater or slowly/rapidly percolating soil, or near drinking water supplies, wetlands, coastal ponds or other water resources.
The cost of a septic tank alone runs about $500 -$1,800 depending on size (ranging from 300-1,000 gallons) and type. Piping and other needed items adds another $100 -$200 to the total cost of materials.
WaterTanks.com illustrates basic tank installation procedures. However, many regions require a septic system to be designed and installed by trained and licensed professionals; contact your local or state sanitation department for details.

What should be included:

Septic systems are used when sewage treatment plants are not accessible, which usually means rural or suburban homes on large lots. The septic tanks itself is a large, underground, watertight container made of concrete, fiberglass or plastic (polyethylene).
The North Carolina State University Ag Extension explains how septic systems work and where they can be used.
It can take several days to a week or more to install/replace a septic system. The process involves extensive digging, often with heavy earth-moving equipment.

Additional costs:

Most counties and states require a building permit for installing or replacing a septic system, at a cost of $250 -$1,000 or more depending on the location and the complexity of the project. Check with your local building/planning department for details.
Installing a septic system usually involves extensive digging and damage to the landscaping; replacement turf and other plantings can run $100 -$1,000 or more.

Discounts:

In a cluster septic system, each house has its own underground septic tank but they all feed into one drainfield/leachfield/soil absorption system. Typically installed by developers, a cluster septic system splits the cost of the drainfield installation and maintenance among many houses.

Shopping for a septic system:

Check with your local sanitation department to see if they maintain a list of licensed septic installation contractors.
Laundry-Alternative.com provides tips for finding a good septic contractor.
Referrals to septic contractors are available through the National Onsite Wastewater Recycling Association.
Ask about training and experience. Check that the company is properly bonded, insured and licensed in your state; and see if there are any complaints with the Better Business Bureau.

Article updated July 2008