How Much Does It Cost To Replace A Septic Tank

What is a septic tank?

A septic tank is an underground structure that treats contaminated water from your home. These tanks are usually made of concrete, fiberglass or polyethylene, and they’re part of a larger septic system that delivers the wastewater to the tank and discharges it once it’s been treated.

Septic tanks can be more affordable than connecting to a sewer system, and they’re often better for the environment. However, they can require more maintenance and more care regarding what you put down your drains. If you’re building a new house, you may have a choice between a septic system and a shared sewer system, but most homeowners just stick with what their house was built with.


Cost to Install A Septic System for an RV

If you’re building a more permanent septic system for your RV, then prices are the same as installing one for a house at $3,300 and $5,000. An RV these days is generally understood to be a mobile vehicle. The septic system in an RV consists of a black water or wastewater tank, the contents of which are dumped into a sewer connection or dump station. It will need to be flushed, cleaned, and sanitized regularly to stay in good working order.

Return to Top

Additional Factors to Consider

A septic tank can either be installed under or above the ground. Installing a tank underground is costly because of the digging and footing preparation involved.

Underground septic tanks require a drain field that can be fitted with a soakaway. The soakaway makes the tank require less emptying because it allows for some of the wastewater to filter into the ground. This can reduce your spending over time.

Different jurisdictions require different permits. Some require that an inspector visit and approve the site, which could entail a fee. Septic tank permits vary from state to state, but in general, you’ll need to pay renewal fees upon the expiry of your permit.

Septic Tank Cost: Do I Need a New Septic Tank?

The average lifespan of a septic tank is approximately 20 to 40 years, with some lasting even longer. Replacing a septic tank is a rare event within that lifespan as long as careful maintenance and regular inspections are performed. Here are a few of the more serious problems that may require a new septic tank installation.

Standing Water

Without a heavy rainfall, broken sprinkler line, or flooding river to blame for the extra water that’s visible on a part of a property, the remaining culprit is likely an oversaturated drain field or a broken pipe or septic tank. The excess liquid is not being properly absorbed into the ground and could be contaminated with bacteria.

Strange Smells

Contrary to popular belief, septic tanks should not smell all the time—after all, they are buried underground. A new odor of sewage can be caused by a septic tank that is too full and leaking solid waste. The leach field could have been contaminated and oversaturated by black water or contaminated wastewater.

Slow Draining

If the septic tank gets too full, all pipes will drain more slowly as there is less space for them to drain properly with gravity. When only one pipe drains slowly, there may be a blockage in only that pipe. If all toilets are flushing slowly or being backfilled with waste, a problem with the septic system needs to be addressed with repair or replacement.


Patchy Grass

When grass covers a septic tank and drain field, some problems can be identified by seeing patches of grass that suddenly grow more vibrantly. A wastewater leak can be an unsanitary method of watering or fertilizing the grass or small plants that grow above the system. Patchy grass may not be accompanied by a foul odor, but it’s best to ask for a professional inspection.

Aged System

Many homeowners who install a septic system move to a new home before the system ever needs to be replaced. However, if an older home was purchased that has an older system and repairs are frequently being made (or the system requires frequent pumping), it’s probably time to consider replacing the septic tank system.

House Size Increase

Since the size of the house is the primary determining factor for how large a septic tank is, expanding the home or increasing the water usage with additional people will affect the life of a septic tank. These are important factors that can affect whether the septic tank is sufficiently large enough to accommodate the home.

Nearby Contaminated Water Sources

Wastewater contamination can occur in nearby water sources if a septic tank has leaked improperly. If nitrate, nitrite, or coliform bacterias are discovered in natural water sources near the home, it’s important to investigate whether your septic tank is the source of the contamination.


Why you need a new septic tank

AXL/Shutterstock AXL/Shutterstock

There are many reasons why you might want to replace a septic tank. These begin with a natural lifespan calculation of the current system, but this isn’t the only factor at play when it comes to replacing your wastewater treatment system.

A damaged tank should be repaired or replaced immediately

If your septic tank has been damaged or shows some of the telltale signs of leaks or other seepage issues, then inspecting the system should be your first priority. Aqua Test Inc. notes that a damaged tank can be detrimental to the surrounding ecosystem of your lawn, and the best way to catch these issues before they develop into a significant problem is to check your tank for damage every five years.

If the tank is damaged beyond repair, then an immediate replacement is simply necessary. Just like broken windows, a leaking roof, or cracks in the foundation, the septic tank is a feature of the home that can’t be pushed down the road for replacement once the time has come.

Your septic capacity needs may change over time

If you’ve recently renovated your home to include an in-law suite, added bedroom, or any other expansion to match the needs of a growing family, you may also require a larger septic tank to keep pace with your wastewater requirements. Aqua Test Inc. notes that a 900 or 1,000-gallon tank is typically appropriate for a standard layout that supports one to three bedrooms. This equates to about 500 gallons of water used per day.

Alternatively, a five-bedroom home averages about 900 gallons of water usage each day, resulting in a larger tank capacity requirement. If you’ve added new living space to support an in-law or any other new addition to the property, upgrading from a smaller tank to one that holds 1,500 gallons will help support the ongoing lifestyle and comfort that you’ve come to expect from your home.

Septic System Repair Cost by Type of Problem

There are many situations where homeowners do not know which components have caused the problems. However, they know something must be wrong due to strange smells, overflowing tanks, or other unpleasant or unusual situations. If you notice something strange going on with your tank, contact a professional and call them out to take a look and diagnose the issue. The table below shows common complaints and average repair costs for each.

Type of ProblemAverage Cost to Repair (Labor Inclu

Type of ProblemAverage Cost to Repair (Labor Included)
Backing Up$250 – $1,000
Septic Smell$250 – $5,000
Loud Noise$250 – $10,000
Tank Overflow$250 – $10,000
Water Not Draining$250 – $10,000
Clog$350 – $1,000
Ground Sinking Around Tank$1,000 – $10,000
Leak$1,500 – $20,000
Collapsed$2,000 – $10,000
Crack$2,000 – $10,000

Septic Tank Backing Up Into Bathtub

If you have a septic tank backing up into your bathtub, the repair may cost from $250 to $1,000. This problem can be caused by an issue with an effluent filter or an outlet baffle. It causes sewage to back up into the home or near the tank. If these two components are in good shape, the issue may be related to the inlet baffle. Unclogging should rectify the problem.

Septic Smell in the House

Repairing a septic system causing smells in the home costs between $250 and $5,000. In most cases, this issue is caused by a pipe clog or blockage preventing waste from flowing properly. It may also be caused by a full tank that needs to be emptied. Cleaning it regularly prevents this issue. Pipe clogs and other issues that create a foul odor from the tank should be handled by experts.

Septic Tank Making a Loud Noise

The cost to repair a system making loud noises ranges from $250 to $10,000. Some noises can be caused by the need to pump the tank, which is relatively inexpensive. However, these noises can also result from cracks and holes in the tank. Pump issues or drainfield problems may also create loud noises signifying the need for repairs.


Repairing an overflowing tank averages $250 to $10,000. There are a few possible causes of this problem. It might be that it needs to be pumped, which is cheap and simple. However, it might signify a more serious clog or leak that needs more expensive repairs. This is often the result of plant or tree roots that manage to get into the tank itself. This can be a serious situation, and a professional should be tasked with repairs as soon as possible.

Water Not Draining

Fixing a tank that does not drain costs $250 to $10,000. A common reason for this problem is a blockage in the tank or pipes, which may have become clogged with sludge, dirt, or tree roots. It might also be an issue with the distribution box, or the tank could need pumping. When the tank is filled with water, it can back up into the main line or even find an outlet inside a home. This serious issue should be handled by a professional due to the potential for making the problem worse.

Clog Between House and Septic Tank

The average cost to repair a clog between the house and a septic tank runs about $350 to $1,000. In some cases, this occurs due to the tank not being unclogged recently. This causes the tank to fill with waste which can backup the toilet or cause sinks and tubs to drain more slowly than usual. If a clog is present, pipes may need to be drained. If this is not the solution, the filter or baffle may need to be repaired.

Ground Sinking Around Septic Tank

Repairing a tank with ground sinking around it ranges from $1,000 to $10,000. This issue might be caused by a leak, causing water to flow out into the surrounding soil and creating a small sinkhole. A repairman must take a closer look and identify the issue’s cause before providing a repair quote. If a tank has been abandoned or is failing, it can also cause a sinkhole which may cause damage to the area nearby. Therefore, filling in or disposing of old tanks when new ones are installed is essential.

Septic Tank Leak Repair Cost

Repairing a leaking tank costs $1,500 to $20,000. One of the most common areas of the leak is the leach field. Various potential leach field problems might be causing this issue, and it could also be connected to damage in and around the tank. In the worst-case scenario, you might need a full leach field replacement. Less intensive leaks can occur at the tank and any lines and pipes associated with the system.

Septic Tank Collapse Repair Cost

If a septic tank experiences a collapse, the repair costs range from $2,000 to $10,000. This is most common when it has not been maintained or inspected in the recent past. The causes of a collapse include pressure from above the ground, the growth of tree roots into the tank, or an aging structure. If it is no longer holding water, this hastens the process of collapse. The walls can also collapse. This is most common in older units made of cinder blocks rather than modern models.

Cost to Repair Cracked Septic Tank

Repairing a cracked septic tank costs between $2,000 and $10,000. Seasonal changes like thawing and freezing, shifting ground conditions, and additional environmental factors can cause a tank to crack. Some cracks are simple to repair, while others take additional work, leading to more expensive repair costs.


A new septic tank or septic system, either for new construction or an existing property, will always cost at least a few thousand dollars. The national average cost of professional installation is about $5,828, with a typical range of $3,138 to $8,518

The overall cost of the project depends on the type of septic system you use, the size of your home, and any additional services you may need to complete the installation. Though the typical price range is a good set of guidelines, keep in mind that you could end up paying as little as $1,013 or as much as $18,163

Most importantly: DON’T attempt to install your own septic tank unless you’re a professional plumber or other specialist experienced with septic systems. No matter how handy you are, no matter how much money you think you’ll save, the risk of DIY in this case isn’t worth it. 

Main Photo Credit: Andy Rogers / Flickr / CC BY-SA 2.0

Jordan Ardoin is a writer and indoor plant enthusiast hailing from Florida. In her spare time, she enjoys chasing her two cats around the house and trying to keep her houseplants alive.

Bottom line

There’s a lot to think about when dealing with septic tank issues. Getting professional advice is important, but it helps to know what to expect so you can make educated decisions.

Whether you’re budgeting for a new tank or trying to keep your system running, it’s a good idea to shop around, read reviews and get multiple quotes to learn about your options.

If you’re just planning ahead or worried about septic tank costs down the line, consider a home warranty to help offset the costs. Read up on what they cover and whether they’re worth the money to learn more.

What Size Septic Tank Do You Need?

Septic tank size is typically determined by the number of bedrooms your home has. This is used as a way to estimate how much water will flow through the system daily. Generally, the larger the system, the higher the cost.

Two Bedrooms

A two-bedroom house requires a septic system with a minimum of a 750-gallon septic tank. However, in many municipalities, a 1,000-gallon tank is the smallest size allowed.

Three Bedrooms

A three-bedroom house will need a minimum of a 1,000-gallon water tank, which regularly handles about 360 gallons of water per day.

Four Bedrooms

A four-bedroom home requires a larger tank with a minimum volume of 1,250 gallons. It handles around 480 to 600 gallons of water per day.

More Related Articles:

How much does a leach field rejuvenation cost?

Depending on the size of your drain field, rejuvenation can typically cost anywhere from $1,500 to $5,000. During a drain field replacement, your plumber will dig out the leach field before installing a new one.

What is the difference between rejuvenation and replacement?

Leach field rejuvenation can be done for drain fields that just need cleaning up. This is done when the leach field gets clogged, typically with a mixture of solid waste and wastewater. This process helps the soil absorb everything better. Leach field rejuvenations also include having your septic tank pumped.

Septic Tank Systems and Materials

The price of your new septic system is based on the size of your home, including the number of bedrooms, the type of system selected, and your septic tank’s material. Below is a list of various treatment systems and tanks available and the standard prices.

Conventional Septic System

A conventional septic system uses gravity to move household sewage into the septic tank. Sewage is separated into layers, with solid waste settling at the bottom and liquid sewage rising to the top.

When liquid sewage rises to the level of the outflow pipe, the liquid waste flows into the drain field, where it decomposes further. These conventional septic systems are usually the most affordable, with an average cost around $2,000 to $7,000.

Anaerobic Septic System

The anaerobic septic system uses anaerobic bacteria to break down waste in the septic tank. These systems don’t require additional chemicals or power. They serve as an affordable option for homeowners.

However, anaerobic systems are not effective at cleaning the tank and require a larger drain field to work correctly. The added size increases the average cost to $3,000 to $8,000.

Alternative Septic System

An alternative septic system collects sewage in the same way as a conventional system, but it breaks down the sewage in the tank using oxygen instead of naturally occurring bacteria. Drain fields for alternative systems generally need less land and release cleaner wastewater. However, this benefit comes at an increase in cost, with systems usually priced around $4,000 to $15,000.

The following types of alternative septic systems are available for homeowners:

  • Chambered septic system: Replacing the need for a gravel/stone system, chambered systems use gravelless drain fields with leaching chambers for the filtration. They are ideal in areas with high groundwater tables or limited gravel.
  • Constructed wetland septic system: Similar to the natural process that occurs in real wetlands, this system cleanses wastewater using bacteria, microbes, and plants. The waste then helps those plants to thrive. This design is the most eco-friendly septic system available.
  • Drip septic system: Drip systems are made to “irrigate” septic water over a larger area using long tubing throughout the leach field.
  • Evapotranspiration septic system: These systems use a large open-air tank to allow the effluent to evaporate naturally. This type of system works best in climates that receive abundant sunlight and heat.
  • Pressurized septic system: This system focuses on using pressure to distribute effluent evenly. It can be paired with other septic systems that focus on water treatment.

Engineered Septic System

Engineered septic systems are the most complex and are generally needed due to poor soil or the home being situated on an uphill slope. Just like alternative and conventional septic systems, engineered systems collect and separate waste in a tank. Instead of relying on gravity to drain, the liquid waste needs to be pumped into the leach field to distribute throughout the land evenly. These systems generally cost $7,000 to $20,000.

Below are some examples of engineered septic systems:

  • Mound septic system: Mound systems employ mounds of sand to clean the wastewater instead of a typical leaching field.
  • Aerobic system: By pumping oxygen into the treatment tank, these systems generate naturally occurring bacteria to process the waste.
  • Recirculating sand filter system: This septic system uses sand to filter effluent out after leaving the pump tank. The treated water then flows to the drain field. This sand filter septic system works best in areas near bodies of water or with a high water table.

Septic Tank Materials

Several different materials can be used for your septic tank.

Here are the most common types available for your home: 

  • Concrete: Concrete tanks are durable and rust-proof but are hard to repair if damaged. Depending on the size, concrete tanks can cost up to $2,000.
  • Plastic: Plastic septic tanks are cost-effective but prone to damage. They cost around $1,200.
  • Fiberglass: Fiberglass tanks are stronger than their plastic counterparts but can be shifted or displaced if the water table rises too high. These tanks can cost up to $2,000.
  • Steel: Although steel is considered a durable material, steel tanks are not used in newer installations since they are prone to rust over time. These tanks are usually found in older installations and should be replaced with a newer option when they begin to deteriorate.

Installation Costs

The final costs for having a septic tank installed are the actual installation or labor costs. Hiring a professional will increase your costs, but it not only means that the installer has a good idea of what they are doing and will know how to combat any problems, but you will have a person or contract to fall back on if things go wrong, giving you greater peace of mind.

You should get a quote for the work, but expect labor costs to come in between $500 and $5,000 for this kind of project.


Leave a Comment