How Much Does It Cost to Redo a Septic System?

Septic system

A septic system will need to be replaced every 15 to 20 years, or if you notice an awful smell in your backyard that can’t be mistaken for anything other than a septic leak.

It’s understandable to not have much knowledge about replacing or repairing septic systems since it’s not a typical project to undertake. But it’s imperative to gather knowledge and prepare before starting a project to redo your septic system if you want the best results. That’s why we’ve compiled this easy-to-read article to guide you through planning for the whole process.

To know how much it costs to redo a septic system in your home, keep reading!

Average Cost to Redo a Septic System

Across the US, the average cost to redo a septic system adds up to around $7,150. The average range for septic system replacement costs lies between $3,100 and $9,800. Most medium-sized homes will use a 1000-gallon tank that will cost between $2,100 and $5,000 to install with the full system.

Septic systems are installed in homes that are not attached to a municipal sewer plant to collect, treat, and dispose of their wastewater. Most of the cost associated with installing a septic system can be attributed to the underwater septic tank that collects wastewater and a soil absorption mechanism that treats and releases clean wastewater into the soil.

The minimum cost for a septic system repair job is around $475, which will only involve minimal maintenance and repairs. Costs can actually reach as high as $50,000 in cases where a big septic system failure has caused extensive damage and requires full repair and replacement.

Factors That Affect the Cost to Redo a Septic System

Septic system replacement costs can differ widely for each individual project. As responsible homeowners, we need to know what factors can affect the price of remodeling. Here are some of the factors you should consider:

  • Tank Size: tank size can have a major impact on the overall cost of the project, as the prices for installation are also higher for larger tanks
  • Septic System Type: there are two types of septic systems: anaerobic and aerobic. Aerobic systems are a lot more expensive. More on this later.
  • Tank material: tanks can be made up of concrete, plastic, fiberglass, or steel. Each material will vary in its utility and price.
  • Soil makeup: the hardness and quality of the soil will determine the excavation costs you incur.
  • Permits: some municipalities will require you to get permits to install a new septic system. These can have an impact on your overall cost.
  • Labor costs: this job is very labor-intensive, so expect to dish out a lot of money for the installation. 

Anaerobic vs. Aerobic Septic System Replacement Costs

This is the first major decision you have to make as a homeowner. This will significantly impact your total cost to redo a septic system. You must choose whether to install an anaerobic septic system or an aerobic one.

Anaerobic Septic System

Anaerobic systems are usually the more common choice for most homeowners thanks to their lower price and easier installation. They have a simple design consisting of a pipe that carries wastewater from the house to the tank and another pipe that leads effluent from the tank out into the drain field.

The system consists of anaerobic bacteria that process and treat the waste in the tank. This system will cost you anywhere from $2,500 to $5,000 in total.

Aerobic Septic System

Aerobic septic systems are superior in quality to their anaerobic counterparts. They use a motor and timer to pump oxygen into the tank to promotes the growth of aerobic bacteria that break down solid waste. This system involves more than one tank as the water treatment process creates cleaner water that is often used for irrigation. Biofilm or sand filters in the drain tile are used to ensure thorough waste cleaning.

This system is clearly more complex than an anaerobic one, so costs are much higher. They cost around $10,000 to $25,000.

Septic System Replacement Costs: Groundwork

We need to plan and get all our preparations done before any work can begin on replacing or repairing your old septic system. We will need to think about the red tape that could possibly hinder our work. You may need to get a building permit to begin any construction work, depending on where you live. Building permits can cost anywhere between $400 and $2,600; however, septic tank work permits tend to hover around the $1,000 price.

You will also have to gouge how much excavation is needed to allow work to begin. Not only that, but you will also have to consider the cost of updating or repairing the landscape once the project has been completed.

Excavation costs will vary based on your soil’s hardness and quality, the number of plants that need to be removed, and the type of excavation equipment used. Excavation costs will typically fall between $1,200 and $4,500. You can often negotiate with your contractor and get a discount by including excavation prices in the cost of the whole project.

These additional expenses can pile up and affect the total cost to redo a septic system, so it’s essential to plan ahead and include it in your budget.

Septic System Replacement Costs: Parts

You don’t always have to replace the whole septic system. Sometimes, you just have to replace the parts. Let’s check out cost of replacing all the different parts of a septic system.


The baffle’s primary function is to prevent scum buildup in the outlet pipe or inlets within the septic tank. This small device is very important to the health of a septic tank. If you replace a worn-down baffle early enough, it can save your septic tank from possible damage and you from spending thousands of bucks. You can expect to spend around $300 to $500 on replacing a baffle.

Drain Field

The price to replace a drain field can vary significantly depending on a lot of factors. The cost can range from $2,000 to $10,000 for a single job. The drain field serves an important function in your septic system by dispersing the wastewater back into the soil. You may first notice an issue in your drain field by recognizing an odor of sewage or a swampy/damp area in your yard.

The cost is divided in the following way: You will have to pay around $30 per linear foot to excavate your old drain field. A further $9 to $12 per linear foot will be needed to install the new drain field. It’s vital to fix a flooded drainage field as soon as you notice an issue.

Tank Pump

A tank pump is a device that extracts effluent from your tank out into the drain field. You can generally expect to pay between $500 to $1,300 to replace a broken tank pump.

Your septic system may not have a pump installed if it is located on the same level as the drain field. However, this septic tank will also require a pumping job every two to three years. This would cost around $380 in most areas.

Tank Filter and Lid

Filter replacement is a routine and common job. High-quality filters will cost around $200 to $290, including installation.

The tank lid is placed on top of the access route of your tank. If you have a concrete lid, it can be prone to cracks that make it dangerous for unaware kids and animals. Metal tank lids are susceptible to rusting, so they will also have to be replaced at that point. Replacement lids will cost between $30 and $80, excluding installation charges.

Septic System Replacement Costs: Plastic vs. Concrete vs. Fiberglass vs. Steel

Septic tanks are available in different materials. These include concrete, plastic, steel, and fiberglass. Let’s check out the prices of each material. The final price you pay will depend on the size of the tank you’re buying.


Plastic tanks are quite affordable. They’re lightweight, readily available, and easy to install. They are not approved for use in some states. You can expect to pay around $800 to $2,000.


This is the most popular choice of septic tank material among American homeowners, thanks to its durability. It will cost around $720 to $2,200.


Lightweight and strong, fiberglass is the highest quality material you can use for your septic tank. You will likely have to pay between $1,600 to $2,100.


We’re not going to list the price for these tanks as they are no longer used in modern septic systems. Most areas will have regulations against their use as they are prone to rusting and other problems.


Before we finish, we would like to suggest that you get bids from several different licensed septic system installation contractors. Make a list of questions, and don’t be afraid to ask anything that is on your mind. Only select companies that have a history of excellence, along with the right certifications and licenses.

If you notice any small problems in your septic system, call for repairs quickly to prevent having to replace the whole system.

We recommend that you visit our website if you are looking for more tips on all types of building, remodeling, restoring, and DIY projects.

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