How Much Do Septic Systems Cost?

Person repairing a pipe in a septic system

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How Much Do Septic Systems Cost?

Septic systems are common in rural areas, where municipal sewage treatment facilities are scarce. They help clean, treat, and dispose of household wastewater and are usually located in the backyard or some other area on the property.

If you’re building a home in a rural area or your current septic system has broken down, you may need to install or replace the system with a new one before inhabiting the property. The cost of this can vary greatly, depending on the size of the septic tank you require, as well as other factors.

The Tank

Most of your septic system cost will come from the tank—the receptacle that holds the water while it’s being treated and clarified. Tanks come in all different sizes and can be made of steel, concrete, fiberglass, or polyethylene.

  • Concrete tanks are the most popular, the longest-lasting, but also the most expensive.
  • Steel ones are the least-used and most susceptible to corrosion.
  • Plastic and fiberglass tanks come at a lower-cost but are vulnerable to structural damage and shifting.

Here’s what you can generally expect to pay for the septic tank itself:

  • 1,000-gallon tank (three-bedroom home): $600–$1,000
  • 1,200-gallon tank (five- to six-bedroom home): $1,200–$1,600
  • 2,000-gallon tank (small building): $1,800–$2,300
  • 3,000-gallon tank (large building): $2,900–$3,900

A 2,000-gallon tank can service a building of about 14 occupants. Anything larger would require a 3,000-gallon tank.

Preparing the Site

You’ll need to prep the site before installing the tank and system — and that means excavating, removing landscaping, and treating the soil. Depending on the size of the area, the plants and trees near it, and the state of the soil, this may require specialized machinery. Generally, the cost ranges anywhere from $1,200 to $4,500. You will also likely need a soil test to test its drainage features; this usually runs between $100 and $400.

Parts & Gravel

Aside from the tank, you’ll also need a pump, gravel to fill your drain trench, and piping and risers to carry water between the tank and your home. Here’s what you should budget for the parts and gravel: 

  • Gravel, stone, fill dirt and topsoil to set a new tank: $500–$1,000
  • Piping, fittings, and risers: $50–$500
  • Tank pumps: $800–$1,400 (not all septic systems require these)


Many cities and municipalities require a building permit to install a septic tank, so check with your local building authority before moving forward with your project. The cost of the permit includes a review of the septic system design mock-ups and a minimum of two inspections of the system during installation. These permits all-in can cost anywhere from $400 to $2,500.

Design & Installation

You’ll want an engineer to help you determine the proper placement and type of septic system for your property before starting any work. They can create detailed plans that your contractor can then use to build out the system. When combined, design and installation usually run anywhere from $3,102-$9,270, with the national average at $5,898.

If you’re considering DIYing your septic system install, make sure you’re well-versed in local code and that you have the proper permits in place.

Unpermitted tank installation may lead to problems with insurance, and it could make the home harder to sell later on down the line.

When in doubt, consider a professional contractor to do the job according to local building codes and permitting requirements.


Your septic system cost doesn’t stop at installation. As long as you’re in the home, you’ll need to dedicate funds to maintaining and servicing it year after year. This means getting regular inspections and pumping the system every three to five years to remove sludge and scum build-up. Pumping costs between $300 and $500, while a septic inspection is $260 to $420. You might also want septic system insurance on your radar to protect you from flooding or other damage.

Get Guidance

The National Onsite Wastewater Recycling Association is a good resource for homeowners with septic systems or those who are considering installing one. The Environmental Protection Agency also has lots of literature on septic systems and their maintenance. You may also look to your local sanitation office for recommendations on septic engineers and contractors in your area.