How Much Does a Septic Tank Cost? A Guide To Septic Systems

How does a leach field work?

Septic systems filter the liquid waste from the solid. Solid waste will sink to the bottom of the septic tank and forms a sludge.  The liquid waste like oils and grease will float to the top. Helpful anaerobic bacteria eat away at the sludge. This breaks the particles down and creates a scum layer at the top of the surface.

This is where your leach field comes in. When solids are filtered through your septic tank, the filtered wastewater – also known as effluent – goes out into perforated pipes. Your field pipes bring the water into your drain or leach field.

Your drain or leach field’s gravel or soil further filters the effluent and removes impurities. Then, the effluent is percolated into the soil. This final process is what removes harmful coliform bacteria.



How to Prepare for Your Septic Tank Installation

To ensure septic tank installation goes smoothly, here are a few tips to keep in mind.

Receive Multiple Estimates

Before any excavation or signed paperwork, receive estimates from licensed septic tank installers and read reviews about each company using trusted, third-party consumer reviews. Ensure the contractor you select holds the proper insurance and licensing and includes necessary preparations like excavation and drain field testing in their estimate.

Test the Soil and Obtain a Permit

Septic systems rely on permeable soil surrounding the tank to absorb and naturally treat liquid residue so that it doesn’t contaminate runoff water or leak into the water table. This area is known as the drain or leach field.

Before installing a septic tank, you’re legally obligated to obtain a percolation or “perc” test. This test confirms the soil meets requirements set by the city and local health department. Usually, the soil is required to have adequate amounts of permeable contents like sand or gravel. Once the land passes the percolation test, you’ll be able to obtain a permit and start the installation process.

Note: If you want to put a septic tank on a piece of land, it must pass the percolation test. We recommend ordering a test before purchasing the land you want to use for residential purposes.

Plan for Excavation

Heavy equipment is needed to excavate the large amount of land necessary for a septic tank. If you currently reside on the land, make sure to budget landscaping costs to fix any damage incurred during excavation.

If you’re building a new home, schedule the excavation at a time when it’ll have minimal impact on the construction process. Typically, this is before paving the driveways and sidewalks, but after the main frame of the home is built.

Signs That a Septic Tank Needs Repairing

Septic tanks have numerous parts, meaning several things can break or wear out. Symptoms that might mean that it needs repairing vary based on the issue. Puddles or wet areas located above the septic tank are one sign. You also may smell the odor of sewage when you are near the tank. If the grass has become more dense and colorful, your tank may need to be repaired. Plumbing inside the house that does not drain properly or backs up is another sign. You may notice a depression or sunken area over the tank, gurgling in other drains when one fixture is used, or a strong odor coming from the drains when repairs are required.

Not all of these necessarily indicate a repair is needed. Some may mean it is overdue for regular service or a separate issue with the plumbing. You should still have the system checked to ensure no serious issues need an emergency repair.

Septic Tank Cost: Replacement Parts

As with any mechanical system, issues are bound to arise. Septic tanks that are properly cleaned and maintained can last an average of 20 to 40 years. While some of the problems with septic tank systems are easy to solve, others will require significant assistance from a professional. From baffles to tank lids, these are the most common parts of a septic tank that may need to be replaced or repaired.

Baffle Replacement

Baffles are designed to help prevent scum from clogging inlets and pipes. Baffles that fail or get clogged are a common issue, and replacing them is usually much cheaper than replacing the entire tank. Replacement costs range between $300 and $500 including labor.

Septic Tank Pump Replacement

For septic tanks that require a pump to push the effluent from the tank to the drain field, it’s possible that the pump may fail to do the job properly. The average cost to replace a failed pump ranges between $800 and $1,400 including labor.


Tank Lid Replacement

A broken or rusted lid is a minor repair that costs between $30 and $70 before labor. Metal lids are the easiest to replace if they have rusted over, while a concrete lid may require some special equipment to remove and install the new lid.

Septic Tank Filter Replacement

Replacing a septic tank filter is the most common issue for most homeowners. The cost to have a replacement filter installed on a septic tank averages between $230 and $280.

Septic Drain Field Replacement

If a septic tank leach field or drain field becomes oversaturated, sewage can back up into the house. The average cost to dig out the existing drain field and install a new one runs $7,000.

Septic System Repair Cost by Type of Repair

Many issues can arise with your septic tank, and the cost depends on the problem. Some issues can be repaired quickly and cheaply, but others require more costly parts and long hours of labor, leading to higher bills. The table below shows common repairs and the average price for each.

Type of RepairAverage Costs (Labor Included)Lid$15

Type of RepairAverage Costs (Labor Included)
Lid$150 – $500
Pipe$200 – $800
Pump$250 – $1,500
Outlet Baffle$300 – $900
Wall$500 – $4,000
Line$1,000 – $4,500
Leach Field Rejuvenation$1,000 – $5,000
Septic Field$1,000 – $5,000
Leak$1,000 – $10,000

Septic Tank Lid Repair Price

Repairing this lid averages $150 to $500. This typically needs to be done if there is cracking or other damage on the lid surface. If the surface is not in excellent shape, it may be possible for debris to move through the lid and into the tank. Repairs also may be needed if odors are making their way from the tank.

Septic Pipe Repair Cost

The average cost to repair these pipes ranges from $200 to $800. This is an important repair to handle as soon as damage is noticed. If odor and standing water are found between the drainfield and tank, it is likely that a pipe is broken and should be repaired. If there are issues with the pipe, you may also experience backups in the toilets or showers of the home.

Septic Pump Repair Price

A homeowner having a pump 2 repaired can expect to pay around $250 to $1,500. If there is damage to the pump, it can cause bad smells, sewage backups, pooling water, and slow drains. This pump connects to the home’s internal plumbing and needs to be maintained regularly to keep it in good shape. A damaged pump can be a health hazard and should be repaired by a professional as soon as possible.

Septic Tank Outlet Baffle Repair Cost

Baffle repairs on a septic tank cost between $300 and $900. The baffle is a key component in any septic system because it stops the pipes from becoming clogged. But baffles can wear and may become cracked or damaged. In most cases, full replacements are needed, but you can patch minor damage on some baffles.

Septic Tank Wall Repair Cost

Tank wall repairs for a septic system average $500 to $4,000. The tank wall can be damaged by tree roots, exposure to the elements, and Earth movements. Cracks and holes may lead to worrying leaks if left untreated. Contractors use special equipment to fill cracks and repair damage. While small cracks may not be a problem, larger ones may create additional issues. Once filled, the tank can continue to be used as normal.

Septic Tank Line Repair

On average, repairing this type of line costs about $1,000 to $4,500. The lines are typically made of PVC plastic, ABS, or cast iron and connect the tank with the drainage system in the home. If the line is damaged, the tank will not work as expected. Leaks and other problems can occur. To repair this line, excavation is required to access it. At that point, a professional repairs the line to ensure the system is in good shape and ready to be used.

Leach Field Rejuvenation Cost

Leach field 3 rejuvenation costs between $1,000 and $5,000. This method is used to clean leach fields that have become clogged or soaked with wastewater and solid waste. Rejuvenation essentially gives the soil a helping hand and allows the field to absorb wastewater easily. It also involves pumping the field to remove excess water before adding good bacteria and enzymes to refresh the system.

Septic Field Repair Cost

Repairing the septic field costs between $1,000 and $5,000. The field, also known as the drain or leach field, transfers wastewater into the soil. Drain field problems can develop, leading to nasty smells and soaked ground. You can clean the area and resolve the problem’s root cause without resorting to a drain field replacement.

Septic Tank Leak Repair Cost

Repairing leaks costs $1,000 to $10,000. This wide price range is because there are many possible issues behind a leak. It might be a leak in the line or tank caused by various issues like corroded pipes or damaged leach fields. When the tank leaks, this can change the water level inside and result in the death of the bacteria that break down waste. Signs of a leak include lush grass nearby, a foul odor, or a moist yard in the area near the tank.

7. Seepage Pits for septic system effluent disposal

If you scrolled down in this document to look for information on Seepage Pit construction, that subchapter discussing the design and use of seepage pits for onsite wastewater disposal is published as a separate web page


When to Replace System Components

There’s usually no repair for a drainfield that has failed. You probably need to replace some or all of your system.

There are many ways to combine treatment and drainfield alternatives, and your decisions can have a huge impact on costs as well as on how much landscaping you need to redo and how you can use your property in the future. If you want to reserve land for a future garage, for example, you might be willing to spend more on a compact system.

Even if the drainfield is kaput, you may learn that the septic tank itself is okay. Reusing the tank can save you $1,000 or more—and keeps that part of your yard intact. But if moving the tank would solve a landscaping issue or make future pumping easier, now’s the time to do it.

How do you know if your leach field is failing?

There are a few warning signs that your leach field is failing. Keep an eye out for the following:

  • Pungent odors: If you notice unexplained bad odors in your home, it could be a problem with your leach field. When the effluent and wastewater fail to properly drain, they accumulate on the surface of your soil. This results in a nasty, noticeable odor of sewage.
  • Stagnant water: Excessive accumulation of the effluent can result in standing water. You’ll be able to see unexplained puddles of water in your yard if this is happening.
  • Drainage issues: If you’re experiencing recurring clogs and backups in your home, then you may have drainage problems in your system’s leach field.
  • Increased plant growth: If you notice the grass or weeds are growing faster in the area by your drain field, this is a sign your drain field is leaking faster than usual. The nutrients in the wastewater can fuel plant growth.
  • Return of flow: Our team of licensed plumbers can detect reverse flow issues during routine septic tank pumping and maintenance. Some issues can only be detected from within!

If you notice any of these warning signs, give us a call immediately. We can treat the issue before it becomes a health risk for your family. If there is a sewage backup and immediate issue, we recommend checking your local health department website to learn what procedures you may specifically need to follow, as some factors can vary by location.

2. Deep Septic Absorption Trench Systems

a. Site Requirements for deep trench septic systems

These are used on sites where a usable layer of soil is overlaid by three to five feet of impermeable soil.

b. Design Criteria for deep trench septic systems

(i) There shall be at least four feet of usable soil beneath the impermeable layer.

(ii) The required length of absorption trench is determined from Table 4A based upon percolation tests conducted in the underlying soil.

c. Materials used for Deep Septic Absorption Trench Systems

Deep trench septic systems use essentially the same materials as found at 1. CONVENTIONAL SEPTIC LEACH FIELDS

d. Construction specifications for deep trench septic absorption systems

(i) Trenches are excavated at least two feet into the usable layer and backfilled with aggregate or coarse sandy material containing a low percentage of fines (very small soil particles) more permeable than the underlying material to a level 30 inches below the original ground surface.

(ii) An absorption trench system as described in CONVENTIONAL SEPTIC LEACH FIELDS is constructed in the upper 30 inches of the excavation.

What is a Septic System, and How Does it Work?

A septic system is an underground wastewater treatment structure most often used when a municipal sewer system is not available. They are commonly found in rural areas rather than cities.

A typical septic system consists of a septic tank, a distribution box, and a leach field. A leach field is also called a drain field or soil absorption field. A septic tank will help digest organic matter and separates floatable matter such as grease, oils, and solids from the wastewater.

The system discharges the liquid from the septic tanks into perforated pipes buried in a leech field, designed to release the effluent into the soil slowly.

Although the first septic tanks have been in use since the late 1800s, they did not become popular until the 1960s. Up until that time, a cesspool was common in most homes.

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Septic Tank Cost: Types of Septic Tanks

There are only a few materials approved for septic tank designs, and each have their pros and cons. Adequately maintaining a septic tank can prolong the life of the system regardless of which material is chosen. The most common septic tanks are designed from concrete, fiberglass or plastic, and steel.


Concrete tanks are the most common and durable for an average lifespan of 20 years. Over time, they can begin to crack and allow seepage of liquid waste out and groundwater into the tank, so it’s important to have inspections completed regularly. The average price of a concrete septic tank ranges between $2,350 and $6,750.


Fiberglass septic tanks are a great alternative that resists any rusting, corrosion, and algae growth. They do not expand or contract either. While fiberglass tanks are heavier than plastic tanks, they are still at risk of shifting if water tables change or the ground shifts. These septic tanks cost approximately $1,600 to $2,000.



With an average cost of $830 to $1,900, plastic septic tanks are a lightweight option compared to a concrete tank. They resist rusting and cracking as well. Though the lighter weight can make them easier to install, if installed improperly, they can rise through the shifting ground to the surface or break under shifting pressure.


Stainless steel is a durable metal for many uses, but stainless steel septic tanks are the least preferred style, as those made of this material can break down before their expected 20-year lifespan. Buried in the ground and subjected to corrosive materials, a steel septic tank has ample opportunities to rust or corrode. Older homes for sale will likely need an inspection to review the safety of the tank before they are sold.

Mobile Home Septic Tanks

Mobile home septic tanks are basically the same as fixed home septic tanks in size requirements, permits, and installation. The challenge with a mobile home septic tank system is installing it in a location that will not be driven over by the home itself or trucks moving the home. The weight of the mobile home or trucks could damage the septic tank, so it’s best to review its position before moving the mobile home.


Replacement Costs

Although costs vary according to the size of the leach field, soils and costs of local permits, expect to pay between $5,000 and $20,000 for leach field replacement. It is the most expensive component of the septic system. While areas with naturally sandy soil allow good percolation, or “percing” of the wasterwater downward, clay soils hold water.

The price of replacing your leach field depends heavily on soil type, as the field does not need to be as large for porous soil conditions as it does for less porous soils. If the section of your property containing the leach field is inaccessible and trees or fencing must be removed, that will also add to your costs. You also will need to factor in the cost of replacing sod in the area or planting new grass seed after the work is done.

Paying for Septic Repairs

If you need major septic work, contact your local health department or environmental agency, which may be able to help you find affordable financing or provide tax credits for the work. Some municipalities use money received through the federal Clean Water Act to help finance septic system repairs by offering low-interest loans.


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