how to install septic tank

New Septic System Cost

the average septic system installation cost is $6,350, or $475 to $18,500.

A new traditional anaerobic septic system costs $2,000 to $10,000 for most tanks and systems. Aerobic systems cost $8,000 to $20,000. You might even pay an additional $10,000 or more for an alternative, specialized drain or leach field, depending on your property size, soil composition and water table depth.

Septic systems consist of three main parts:

Septic tank: Either anaerobic (not needing oxygen) or the more complex but more efficient aerobic.
Leach field: After being treated and separated in the septic tank, water runs to a leach field where it will naturally leach through sand, gravel and soil in a cleansing process before hitting the water table.
Piping: You'll need a drainpipe to the tank, then another branched pipe out to your field.

Optional components include:

Dose or pump tank: Pumps wastewater up into mounded or raised leach fields and recycles the water in some types of systems.
Aerator: If you have an aerobic system, you'll need an aerator pump to push oxygen into the tank.

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Anaerobic System Septic Tank Price

The classic anaerobic system installed costs $3,000 to $8,000 on average. Anaerobic systems are typically much cheaper to install than the more complex aerobic system. But they're not as efficient at cleaning the tank so you'll need a larger leach field to pick up the extra workload.

An anaerobic septic system is a relatively simple system consisting of a pipe leading from the house to the tank, and a branched pipe leading from there into the drain field. These systems rely on the presence of anaerobic bacteria (bacteria that do not use oxygen) to break down waste in the tank before further bacterial processing in the soil.

Aerobic Septic System Cost

Aerobic systems, those that require oxygen to function, cost $10,000 to $20,000 on average. If you're converting from anaerobic to aerobic, you'll likely need a second tank, but it'll only cost $5,000 to $10,000 to convert. Aerobic systems break down waste more effectively in the tank than anaerobic systems, meaning you can often use a smaller drain field – great for smaller properties.

An aerobic system is a wastewater system that relies upon aerobic bacteria (oxygen-loving bacteria) to break down waste in the tank. They're more complex than an anaerobic system. You'll need an aerator and an electrical circuit running to the system. In some cases, with small, mounded or specialty fields, you may also need a dose or pump tank to push the effluent (the sewage or wastewater) uphill or out in doses.

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Septic Tank Installation Cost Considerations

Besides the tank and leach field, you'll have a few other fees you'll need to consider in your budget. You may have some of these included in your overall project price, so ask for line-item costs on your estimate.

Excavation costs: $1,200-$4,500
Building permits cost: $400-$2,000
Perc test cost: $750-$1,300

Leach Field Cost

A leach or drain field, part of your septic system, costs anywhere from $3,000 to $15,000 to install. A traditional drain field runs $2,000 to $10,000. The drain or leach field is the section of the septic system that transports the wastewater back to the soil. The first sign of a problem with drain field is often a swampy area in the yard, or an odor of sewage on the property. Drain field replacement can cost anywhere from $10,000 to $50,000, depending on how much remediation you'll need for clogged, flooded fields.

Alternative Septic Systems Cost

You'll want an alternative septic system when you have a small property, high water table, high bedrock, bad soil, or simply want to use less space.

Type	Cost
Mound	$10,000 - $20,000
Sand Filter	$7,000 - $18,000
Drip	$8,000 - $18,000
Evapotranspiration	$10,000 - $15,000
Built Wetland	$8,000 - $15,000
Chambered	$5,000 - $12,000

Mound Septic System Cost

A mound septic system costs $10,000 to $20,000 to install. It's the most expensive system to install but often necessary in areas with high water tables, shallow soil depth or shallow bedrock. It relies upon an elevated mound of sand for the drain field rather than excavating into the soil. Its increased expense comes from both the added machinery needed to pump effluent uphill into the mound, and the materials and creation of the mound itself.

Recirculating Sand Filter Septic System Cost

Sand filter septic systems cost $7,000 to $18,000. They're constructed either above or below ground. They use a pump chamber to push the wastewater through a sand filter prior to dispersal in the ground. The filter box typically has a PVC lining. The pump pushes the effluent through the sand and back to the pump tank where it's then dispersed through the ground.

Drip Septic System Cost

Drip systems cost $8,000 to $18,000 depending on the size. They work like other systems, except they use extensive drip tubing and a dose system. They release smaller timed doses, which work well in shallow soil depths. It costs more than a traditional system, since it requires a dose tank, pump and electricity.

Evapotranspiration System

Evapotranspiration systems cost $10,000 to $15,000. They use a unique drain field setup that allows the liquid to evaporate from the top of an open-air tank. They're only useful in dry, arid climates that see little rain or snow.

Built Wetland System

Built wetland systems cost $8,000 to $15,000, and more if you use an aerobic tank. They mimic the natural cleansing process found in wetlands. It's treated by microbes, plants and bacteria in a wetland tank before passing to the soil. The waste also has the effect of supporting the wetland plants and microbe population.

Chambered System

Chambered systems cost $5,000 to $12,000 to install. They use plastic perforated chambers around pipes often set in sand,. This eliminates the need for gravel. They're quick and easy to install, but more susceptible to crushing forces, like vehicles.

Septic Tank Replacement Cost

Replacing a septic tank costs $3,000 to $10,000. You can expect your system to last anywhere from 30 to 40 years. When the system begins to fail it may crack or corrode, causing the waste to leach into the ground water. When this happens, the well water may become contaminated, the yard may turn swampy and the septic system may stop functioning.

When replacing, consult with your service professional about the pros, cons and costs of upgrading to a more efficient aerobic system.

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Septic Tank Cost by Size

Tank Gallon Size	House Size	Tank Cost
500	1 bedroom	$500 - $900
750	2 bedrooms	$700 - $1,200
1,000	3 - 4 bedrooms	$900 - $1,500
1,200	5 - 6 bedrooms	$1,200 - $1,600
1,500	6 - 7 bedrooms or small duplex	$1,500 - $2,500
2,000	Duplex to small apartment building (~14 occupants)	$3,000 - $4,000
3,000	Small apartment building	$4,500 - $6,000
5,000+	Apartment building or community tank	$7,500 - $14,000

Septic Tank Cost by Type

Septic tanks and septic pump tanks cost $350 to $14,000, depending on the use, material and size. For most residential settings, you'll rarely spend more than $3,000 on the tank itself. Most large, higher-priced units are designed for apartments or community septic systems.

Type	Cost Range
Concrete	$700 - $2,000
Plastic & Poly	$500 - $2,500
Fiberglass	$1,200 - $2,000
Steel	Varies

Concrete Septic Tank Cost

Concrete tanks cost $700 to $2,000. Total installation costs run $2,300 to $6,500. They're one of the most common types installed. They're susceptible to cracking or separation but are usually durable for a couple of decades. It's important to have it manually inspected regularly against cracks and runoff. Inspections and regular cleanings help prolong its lifespan. Your pro can tell you how often to have it inspected, but it's usually anywhere from 1 to 3 years.

Plastic and Poly Septic Tank Prices

Plastic septic tanks cost $500 to $2,500 on average, not including installation. Plastic is a durable, lightweight, relatively inexpensive material. They rarely crack like concrete and can't rust. Because they are so lightweight, plastic can be vulnerable to damage during installation.

Fiberglass Septic Tank Prices

Fiberglass septic tanks cost $1,200 to $2,000 on average, not including installation. Fiberglass doesn't crack easily or rust, but like plastic, is susceptible to damage during installation. The lower weight makes it more susceptible to structural damage, however, and the tanks themselves can shift in the soil.

Steel

You'll likely never see a new steel tank installed. Regardless of how well made one is, they'll eventually rust or corrode. Many local building codes don't allow them, and you'll often only see them in existing installations. Steel isn't durable in the ground and it's the least popular type.

Labor Costs to Install a Septic System

Labor makes up 50% to 70% of your total costs. In a typical installation, labor is more expensive than the price of the tank itself. Whereas the size needed for a 3 to 4-bedroom home may cost in the range of $600 to $1,100, the labor to install can range from $1,500 to $4,000.

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DIY vs. Hire a Septic System Pro

Septic system installation is a complicated process. An improperly installed unit can lead to water pollution, damage to the home and expensive repairs. In addition, an unpermitted installation can make a home difficult to sell and insure. Be sure to interview at least three professionals before choosing someone. For estimates on your project, contact a local septic tank installer today.

FAQs

How many years does a septic tank last?

A septic tank will typically last 20 to 30 years, but can range from 14 to 40 years, depending on:

What it's made of. Concrete tends to require more maintenance, but commercial grade fiberglass and plastic tends to last decades.
How well you've maintained it. Get inspections and pump out your system every 1 to 3 years and pump it out every 3 to 5 years.
Whether it gets vehicle traffic over the leach field. Driving over the leach field compresses it and may cause it to fail.
The composition of the soil. Varying soil types and depths affect how long it may last.

Does homeowners insurance cover septic systems?

Homeowners insurance covers many unexpected and sudden damages to septic tanks. However, they usually do not cover damage caused by a lack of maintenance. Make sure you're pumping and cleaning it yearly.

How much do septic system repairs cost?

Septic system repairs cost $600 to $3,000. Tank repairs usually cost less than $1,500 for each type of repair or part, listed below. Leach fields run $2,000 to $20,000.

Tank Pump: $800-$1,500. A septic tank that is located lower than the drain field may require a pump to bring wastewater up to the drain field.
Annual Pumping Cost: $300-$600. Even a system that functions properly will need to be pumped every two or three years to remove the solid waste.
Tank Lid: $100-$300 to purchase and install. You'll only spend $50-$150 buying the lid and putting it on yourself.
Tank Lid Risers: $300-$1,000. They raise the lid level up to surface for deeply buried tanks.

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