Cost Estimator by Home Size

When figuring out a proper budget for installing your new septic tank, one of the first things you’ll need to know is how big of a tank your home requires. The size of your tank will depend on the size of your home, since larger houses usually have more sinks, toilets, bathtubs, and other sources of wastewater that will end up in the septic tank. 

Use the number of bedrooms in your house to estimate the approximate volume of your septic tank in gallons. A one-bedroom house, for example, will need only about a 500-gallon tank, which would cost $713 on average (not including labor costs).

A house with five or six bedrooms, on the other hand, would need a much larger 1,500-gallon tank costing about $2,250 (again, for only the tank itself).

1 bedroom500$713
2 bedrooms750$1,075
3 bedrooms1,000$1,400
4 bedrooms1,250$1,850
5 – 6 bedrooms1,500$2,250

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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.


Cost to Convert Septic to Aerobic

Converting an anaerobic system to an aerobic one costs $5,000 to $10,000. Anaerobic systems are less expensive, costing $2,000 to $5,000 as a traditional and common septic system with relatively no oxygen in the tank. Aerobic systems support bacteria that live off oxygen and help break down sewage, making them more expensive, around $10,000 to $20,000.

The advantages of converting from an anaerobic system to an aerobic one include the cleaner effluent flowing out of the system, which minimizes the chances of groundwater contamination. If you live somewhere with a high water table, an aerobic system helps prevent water pollution. The main downside is, of course, the higher installation costs. Additional maintenance is also involved, like checking the air injection and electrical systems.

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.

When Should You Hire A Professional To Install a Septic Tank?

The short answer? Always!

Whether you’re installing a septic system where one didn’t previously exist, or you’re replacing your cesspool with a septic tank, you should always hire a professional to do the work for you.

Septic tanks and cesspools are not only very challenging to unearth and access, but the gases and contents within the containers are hazardous to your health and potentially deadly.

Additionally, any mistakes during the installation of your septic system could easily lead to thousands or even tens of thousands of dollars in property damage and fines from the health department.

As such, no homeowner or DIYer should ever attempt to install or replace a septic tank on their own.

How much does it cost to replace a leach field?

Leach field replacements can be some of the most costly services. This is because of the timely process of digging out a new leach field prior to installing a new one. The exact price of your leach field replacement will depend on a few factors. This includes the size of the leach field and your septic system. On average, the price can run anywhere from $5,000 to $20,000.

Before you have your leach field replaced, consider how this will impact future decisions for your property. This includes how much landscaping you’ll do, landscaping costs, and how you’ll use the property if you decide to take on any home improvement projects. Let us know if this is a concern.

Septic Tank Materials

Another factor influencing cost is what your septic tank is made from. Here are some of the most common materials:


Concrete tanks are the most common type of septic tank because they’re durable. Properly maintained, they can last 20 to 30 years. However, concrete may crack over time. Reinforcing the concrete with rebar helps increase its strength under pressure. Installation is more challenging, and extensive equipment is needed because of its weight. The cost for an average-sized concrete tank is $720 to $2,050.


Fiberglass doesn’t weaken when used underground, and it’s nonporous, so it won’t attract algae growth. Installation is easier because the tank is light. Unlike concrete, it won’t expand or contract, so you don’t have to worry about cracking. The average fiberglass tank costs $1,600 to $2,000.


Plastic tanks are light and easy to install. They’re also quite durable. Depending on the type, plastic tanks cost $830 to $1,400 on average.


Despite steel’s strength and durability, septic tanks made of steel can rust can collapse if not properly cleaned. As a result, some local authorities have increased regulations to discourage their use. You’ll usually find them in areas where the system already existed. If you can get one installed, they cost $900 to $9,900.

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.


Ground Preparation

While the drain field can be expensive, it is an important part of the system. Another important element is ground preparation. You will need to clear the land, dig up the earth, and move or remove it. This costs an average of about $1,000 for a standard property and an average septic system.

FAQ About Septic Tanks

1. Can you install your own septic tank?

Short answer: No. While it is technically possible for you to install your own septic tank, the odds are very high that you’ll make a mistake that will cause you much more grief (and cost you much more money) than working with a professional in the first place.Installing a septic tank requires specialized technical knowledge you can’t gain from a DIY YouTube video. Messing up this project could cause water pollution, drive up your home insurance premiums, and make your home much harder to sell. In some places, it may even be illegal for someone without the proper license to install a septic system.

2. How do septic tanks work?

Different types of septic systems work in different specific ways, as we’ve already covered. But these are the basics. Waste from your home (anything that goes down the drain of toilets, sinks, showers, etc.) flows into the septic tank. In the tank, waste separates into three layers: the scum layer on top, liquid waste in the middle, and solid waste sinking to the bottom. Either aerobic or anaerobic bacteria break down the solid waste, which stays in the tank. Liquid waste goes through the filter before moving on to the leach field, which distributes the water into the ground in most systems. 

3. How can you tell when you need a new septic system? There are a few signs to look for that will tell you it’s time for a new septic system, or at least a repair. Signs include: — Standing water in the yard — Sewage smells — Showers, sinks, etc., in the home draining slowly  — Water and/or sewage backing up in toilets, showers, sinks, etc.

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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.


How long will your septic system last?

Your septic system should last from 15 to 40 years. This is such a large range because multiple factors contribute to its lifespan. If a septic system isn’t well-maintained and is damaged, then it will have a shorter lifespan and will require greater care. 

One of the biggest factors that contributes to the lifespan of your septic system is its material. A steel septic tank will rust over time – especially in certain areas with highly acidic soil. Poorly-made steel tanks will also rust faster than others. Rust breaks down the tank, to the point where it bursts or starts to leak. This could create an undesirable smell in your yard and a potential health hazard. Some steel tanks will last barely more than 15 years.  

A concrete septic tank has a much longer lifespan, close to the 40-year mark. As long as the materials are high quality and the installation was done correctly, it should service your home for the next several decades.  

New Septic System Installation Costs

There are two main types of septic systems, conventional and alternative, with those two categories breaking down further according to how the system manages waste. An alternative or aerobic septic system typically costs between $10,500 to $15,000 on average, whereas a conventional or anaerobic system ranges from $2,500 to $5,000 with most homeowners paying $3,500 on average.

 Septic System Types And Cost   Septic System Type

Septic System Types And Cost
Septic System Type Average Cost
Conventional Systems
Gravity or Anaerobic Systems $3,500
Pressure Distribution Systems $7,000 – $10,000
Alternative Systems
Aerobic Treatment Unit $10,500
Mound Septic System $15,000
Sand Filter Septic System $6,000 – $10,000

Conventional or Anaerobic Septic System Cost

Conventional or Anaerobic Septic System Cost

An anaerobic or conventional septic system costs $3,500 to install on average with most homeowners paying between $2,500 and $5,000. These are generally the quickest, easiest, and cheapest to install, and the effluent travels through the septic tank and on into the drain field using gravity.

Aerobic Septic System Cost

Aerobic septic systems generally cost $10,500 to $15,000 on average. The aerobic system breaks down the solids in the tank using oxygen, which is accomplished using a motor and a timer. The wastewater released is cleaner than that produced by conventional systems and can be used for above-ground irrigation needs after it’s sterilized. Additional benefits include needing a drain field half the size of that of a conventional system, which allows for more placement options on your property.

Aerobic Septic System vs. Anaerobic

The main difference between aerobic and anaerobic septic systems are in how they treat the effluent. Anaerobic or gravity systems flow into a drain field while aerobic systems treat the effluent before it reaches the drain field with oxygen, biofilm in the drain tiles, or sand filters.

Mound Septic System Cost

The average cost for an above-ground mound septic system is $15,000, with annual maintenance costing as much as $500. It’s quite possible that the percolation test will come back saying that your soil isn’t of the right drainage quality to have an underground septic system, in which case you’ll have to install an above-ground septic system at two to three times the cost.

An engineered mound system is required when the soil type on the homeowner’s property is either too permeable or completely impermeable, or if there is only a shallow cover of soil over porous bedrock, or a high seasonal water table present. The purification and cleaning of the wastewater is accomplished through a biofilm present in perforated drain tiles. This slows down the water while purifying it before it reaches the water table below. As the name might imply, it will result in a raised surface or mound on your property.

Sand Filter Septic System Cost

A sand filter septic system costs between $6,000 and $10,000 to install on average. The sand filter system is like a conventional septic system, but it uses a pump to distribute the effluent to a filter system—sand housed in either a concrete or a PVC-lined box—a grid of small pipes. The sand filter allows for prefiltering of the water before it reaches the drain field to protect the underlying water table. Sand filters have been known to have a useable life of up to 20 years in some locations.

Pressure Distribution Septic System Cost

Pressure distribution septic systems range in cost from $7,000 to $10,000 on average. They only require a distance of 2’ between the bottom of the system and the water table below, and they use a pump to get the effluent to reach more of the drain field that gravity can’t accomplish unaided.

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How It Works

Anything going down drains and toilets heads into the septic tank. When wastewater and solids enter the tank, an initial baffle prevents wastewater from pouring in. This stops it from stirring up sludge in the tank. The outlet baffle prevents grease and scum from exiting the tank. Within the septic tank, the majority of solid waste settles in the bottom. Bacteria helps break this material down, and sludge forms. Wastewater continues on out to the leach field, usually through perforated pipe on top of a crushed or screened stone bed. Once in the leach field, the wastewater trickles down through the stone bed and into the soil.

In effect, the leach field acts as a giant filter. For best results, the soil in the leach field should be undisturbed and not compacted. Pathogens in the wastewater are absorbed by the soil, causing them to die off. Bacteria present in the soil also helps in the water cleansing process, along with common soil nutrients such as phosphorous and nitrogen. When wastewater can no longer be absorbed by the soil, the leach field fails.


  • How much does it cost to put in a new septic system?

The average cost of installing a septic system is between $3,100 and $9,600, including the system and installation. Anaerobic, gravity, and chamber systems are on the lower end of that average, usually costing $1,500 to $5,000. More expensive systems include the mound system, aerobic, and evapotranspiration and range anywhere from $10,000 to $20,000.

  • How much does it cost to replace a 1,000-gallon septic tank?

A 1,000-gallon tank usually costs between $800 and $2,000, but the price varies depending on the tank material. A concrete tank has the cheapest material cost, between $800 and $1,250, but it is the most expensive to transport and install because of its weight. A plastic tank is slightly more expensive, $830 to $1,400, but its weight makes it much cheaper to install, and heavy machinery is usually not needed. A fiberglass tank usually ranges between $1,600 and $2,000.

  • How many years does a septic system last?

A septic system typically lasts between 15 and 40 years. This is usually determined by the quality of the tank and the drain field. A concrete tank is extremely durable. When constructed well, it is fairly indestructible and can easily last 40 years. The lifespan of a plastic tank is about 30 years. The drain field can also be a limiting factor on the age of the system. The drain field type does not affect the lifespan of the system. However, the quality of the soil and drainage is a huge factor. Not doing maintenance on the system is one way to shorten the life of any system.

  • How many acres do you need for a septic system?

The smallest area a septic system will usually fit in is a ½-acre lot. Most homeowners with small lots opt to use an aerobic system. Most systems, such as an anaerobic or chamber system, typically need at least a one-acre lot. Mound systems need the most space because the mound itself is usually a minimum of 200 feet long.

  • Can heavy rain cause septic problems?

Heavy rain can cause problems for all types of systems because they can flood the drain field. If the drain field floods or the soil is saturated, the effluent septic water cannot effectively drain into the soil. This can cause major backups in the tank and even flooding.

  • How many loads of laundry a day are safe to do with a septic tank?

A small septic system for a two- or three-bedroom home can handle about five loads of laundry per day. This does not include any other water being used and is based on using an old washer with a 1,000-gallon tank. The washer type is a major factor because older washers can use up to 40 gallons per wash. New energy-efficient washers usually use 12 to 15 gallons of water.

  • How much does a 1,500-gallon septic tank cost?

​The average 1,500-gallon tank costs $1,300 to $2,500. This capacity is ideal for a large five- to seven-bedroom house around 3,000 sq.ft. or more. Homes with four, five, or six bathrooms can benefit from a 1,500-gallon tank, usually made of fiberglass or concrete, although plastic tanks are also available.


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