Ashburn, VA

How Much Does A Septic Tank System Cost?

$3,280 – $5,040

The average cost to install a new septic tank system for the home is $3,918, with most homeowners spending between $3,280 and $5,040 for a 1,250-gallon system that supports 3 or 4-bedrooms. A new septic system with two alternating pumps costs $9,571 on average. Get free estimates from septic system installers near you.

Septic Tank System Cost

A new septic tank system costs $3,918 to install on average, with prices ranging from $1,500 to upward of $5,000. Most homeowners spend between $3,280 and $5,040 for a 1,250-gallon system that supports 3 or 4 bedrooms. Septic system installation with two alternating pumps costs $9,571 on average and can go up to $15,000.

Average Septic Tank System Cost

Septic System Cost
National Average Cost $3,918
Minimum Cost $1,500
Maximum Cost $15,000
Average Range $3,280 to $5,040

Your final cost depends on the conditions of current waste lines and the soil where the septic tank will go. When building a home on raw land that is not connected to a local municipality waste system, this type of system is your best option for sewage treatment.

Table Of Contents

  1. Septic Tank System Cost
  2. Average Septic Tank Installation Costs
  3. New Septic System Installation Costs
  4. Septic Tank Cost Estimator By Type
  5. Cost Factors To Put In A Septic System
  6. Septic Tank Replacement Costs
  7. Mobile Homes & RVs
  8. Frequently Asked Questions
  9. Labor Costs & Hiring a Septic Company
  10. Septic Tank System Installers

Average Septic Tank Installation Costs

A traditional septic tank for a 3-bedroom house will cost around $3,900 to install on average. For conventional systems, prices start around $5,000 in the Midwest, whereas in coastal areas, one could cost $10,000 or more. For an engineered system, the costs will average around $15,000 for installation.

Septic Tank Installation Cost Chart

Septic System Installation Cost
Septic System Type Average Cost
Conventional $3,500 – $10,000
Alternative $6,000 – $15,000
Engineered $12,000 – $15,000

Septic Tank Cost By House and Gallon Size

The size of the tank needed for your home depends on the home’s size in square feet and the number of bedrooms. Standard septic tank sizes usually start at 750 gallons for a one- to two-bedroom houses under 1,500 sqft, and go up to 1,500 gallons for a six-bedroom house that is less than 5,500 sqft.

Septic Tank Sizes and Prices Chart

Septic Tank Sizes and Prices
Tank Material Tank Gallon Size House Size Tank Cost
Polyethylene 500 1 bedroom $725
Polyethylene 750 2 bedroom $1,200
Polyethylene 1,000 3 bedroom $1,310
Fiberglass 1,000 3 bedroom $2,300
Polyethylene 1,250 3 or 4 bedroom $2,100
Concrete 1,250 3 or 4 bedroom $2,510
Fiberglass 1,250 3 or 4 bedroom $2,350
Polyethylene 1,500 5 or 6 bedroom $2,340
Concrete 1,500 5 or 6 bedroom $2,660
Fiberglass 1,500 5 or 6 bedroom $2,660

Costs above include excavation with good site conditions, placing of the tank, inlet and outlet fittings, and backfill after hookup. Add the cost of percolation testing, laying about 40 feet of pipes, and building the drain field ($2,000 – $10,000) to get your final cost.

Concrete Septic Tank System Installation On Rural Property

Cost of Septic System for 3-Bedroom House

The cost for a 1,000-gallon septic tank to support up to 3-bedrooms is between $2,190 and $5,200 with most homeowners spending $3,250 on average.

Cost of Septic System for 4-Bedroom House

The cost for a 1,250-gallon septic tank to support up to 4-bedrooms is between $2,310 and $5,400 with most homeowners spending $3,530 on average.

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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 Cost By Type Chart

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

Stainless Steel Septic System Being Installed On Residential Property

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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Septic Tank Cost Estimator By Type

The cost of your septic tank will depend on the material it consists of—concrete, stainless steel, fiberglass, or plastic. The average price of a concrete septic tank is between $720 and $2,050, a fiberglass tank ranges from $1,600 to $2,000, and a plastic tank costs $830 to $1,900.

Septic Tank Cost Estimator
Tank Material Average Cost
Concrete $720 – $2,050
Fiberglass $1,600 – $2,000
Plastic $830 – $1,900

Depending on the construction methods, materials used, and the soil conditions where the tank is placed, a septic tank can last as long as 40 years, and beyond. Given that the average person will move 11.4 times in his or her lifetime, a septic tank installation will probably outlast the average homeowner’s stay.

Concrete Septic Tank Cost

Concrete tanks are the most common type used in the US because of their durability and cost from $720 to $2,050. If they are made well with quality materials and maintained properly, they can last 20 or 30 years or more. Prices for precast concrete septic tanks with inlet and outlet connectors cost: [1]

Concrete Septic Tank Cost
Tank Size Average Cost
1,000 Gallon $815 – $1,250
1,250 Gallon $945 – $1,235
1,500 Gallon $1,100 – $1,520

Excavator Digging and Placing A Concrete Septic Tank System Install

Because of the nature of concrete, they are prone to cracking over time if they are not well made or properly looked after, but you can also get one reinforced with rebar to increase its strength under pressure. Larger equipment is required to install these because of their weight.

Stainless Steel Septic Tank

Despite the strength and durability associated with steel, metal septic tanks will eventually rust and collapse and will likely be outlasted by a neighbor’s concrete tank. Because of this, and increased regulations by local authorities, they are used less and less, and in many regions are likely only to be found in existing systems already installed.

Fiberglass Septic Tank Prices

As with plastic septic tanks, fiberglass tanks are lighter and therefore easier to install. They cost an average of $1,600 to $2,000 for an average 3–4 bed US home. Fiberglass also won’t deteriorate while underground, nor will it attract the growth of as many algae because of its nonporous qualities. It won’t expand and contract either in the way concrete does so that it won’t develop cracks. [2]

Fiberglass Septic Tank Prices
Tank Size Average Cost
1,000 Gallon $1,600
1,250 Gallon $1,810
1,500 Gallon $1,975

Fiberglass Septic Tank vs. Concrete

While possibly longer lasting, fiberglass tanks can cost twice as much as concrete tanks, but fiberglass tanks are approx. 30% lighter than concrete tanks and cheaper to install. Fiberglass also won’t deteriorate or develop cracks like concrete is prone to do.

Plastic Septic Tank Prices

Polyethylene or plastic septic tanks are cheaper to buy and install because they are lighter, costing an average of $800 to $2,000. They aren’t prone to cracking, but they can sometimes break under pressure or in changing soil conditions. In some states, they aren’t approved for use. [3]

Plastic Septic Tank Prices
Tank Size Average Cost
1,000 Gallon $830 – $1,420
1,250 Gallon $1,150 – $1,690
1,500 Gallon $1,270 – $1,900

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Cost Factors To Put In A Septic System

The average cost to put in a new septic system is $3,280 to $9,550. A basic septic system for a 3-bedroom home will cost $3,918 on average with most homeowners spending between $3,280 and $5,040. When you install a system with two alternating pumps, expect to spend $9,500 to $15,000.

Cost To Put In A Septic System
Installation Items Head Average Cost
Basic Quality – Including fiberglass basin, pump, installation from the septic tank or sewer line, 40' pipe run, and automatic float switch (no electric work or pipe included) To 15’ head $3,280
To 25’ head $3,880
To 30’ head $5,040
Higher Quality – With two alternating pumps, 700- to 800-gallon concrete or fiberglass basin, automatic float switch, indoor control panel, high water or pump failure alarm, explosion proof electrical system but no electric work or pipe Per pump system $9,950

Truck With Crane Delivering New Septic Tank

Cost Factors To Install

Installing a septic system is expensive because of the amount of labor involved in doing it correctly. From start to finish, the entire project could take up to three weeks or longer, depending on the permit processing and the complexity of the system you need for your property.

  • Soil testing – A deep hole percolation test by a qualified engineer costs at least $1,000 but ranges between $1,000 to $2,000. Testing will reveal the type of soil in the area and what depths the different layers are at; how deep each layer is; and with the combination of layers, how well suited the area is to filter and drain from the system. Positive results from the survey and test will also allow you to get approval for the drain field (also called leach fields or leach drains).
  • System design – The design of the septic system will generally take between 2–3 weeks to design and cost an average of $600, depending on your location and the complexity of the system. Use the same engineer to do both the percolation test and the system design, as he/she might not accept the test results from the percolation test if done by someone else.
  • Clear the landLand clearing costs around $950 on a quarter-acre for light clearing on flat ground without rocks.
  • Install and connect pipes and tank – To take wastewater from the house to the septic tank costs $25 to $33 per linear foot for excavation, installation, and backfill; and an average of $1,000 to $1,500 for the tank.
  • Leach Field – A drain or leach field costs $3,000 to $15,000. Lay the filtration materials or leach field – $9–$12 per linear foot. Add $25–$33 per linear foot of vitrified clay pipe from the house to the septic tank.
  • Inspection and testing – Pass all checks and final inspection and testing – Building permits cost about $250 to $450, and your local health department will determine which permits are required.
  • Pump Alarm – Add $720 for a high-water or pump failure alarm. Other add-ons and septic tank repairs cost $600 to $3,000 on average.
  • Landscaping costs – Include the costs of any landscaping needed once the tank is installed and dirt has been backfilled over it.

Cost to Install a Septic System Leach Field

The average cost to install a septic system drain or leach field is $3,000 to $15,000. Septic sewer drain fields or leach lines are built with unsaturated paper, piping, and gravel. The fields are excavated, and 4 PVC pipe is laid in 3' deep by 1' wide trenches, after which it’s backfilled, and excess soil is disposed of properly.

  • With 12" gravel base – $30/LF
  • With 24" gravel base – $11/LF
  • With 36" gravel base – $30/LF
  • Add for pipe laid 6' deep – $20/LF

How A Septic Tank Works

Septic System Permit Cost

You’ll need your permit from local authorities allowing construction of your new septic system. Expect to pay about $250–$450. It's usually required to need a site plan: a scale diagram of your land which details the location of the house, outdoor elements (like a detached garage, any walkways, any swimming pools), and the location of the septic system. You can apply for the permit yourself, or your local contractor can include this in the quote. On average the permit will take about 1–2 weeks to secure, and costs include the inspection during construction and after this work is complete.

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Septic Tank Replacement Costs

If you take care of regular maintenance, you won’t need to think about replacing your treatment system for many years. Most tanks store three years’ worth of a home’s wastewater before they are due to be emptied/pumped. Septic tank pumping costs an average of $370 every three years or about $0.25/gallon.

Septic Tank Replacement Costs Chart

Septic Tank Replacement Costs
Replacement Item Average Cost
Drain Field Replacement $3,500 – $11,000
Tank Pump Replacement $500 – $1,200
Tank Removal $5,500
Tank Baffle Replacement $23 – $44
Tank Lid Replacement $30 – $65
Tank Filter Replacement $230 – $280

Excavator Installing New Septic Tank For Residential Community

Septic Drain Field Replacement Cost

Septic drain or leach field replacement will cost between $3,500 to $11,000 with most homeowners paying a total of $7,000 on average. It will cost about $30 per linear foot to dig up the old leach field and $9 to $12 per linear foot to lay the new filtration materials or leach field. A drain field will flood if it gets overloaded with too much liquid, causing sewage to back up in toilets and sinks.

Septic Tank Pump Replacement Cost

When your septic pump goes out, it will generally cost between $500 and $1,200 to replace. A pump is required to bring effluent up to the drain field. The pump is an essential piece due to the fact you need to pump your system every 2 to 3 years for about $370.

Septic Tank Removal Cost

Septic tank removal includes emptying the tank first and then removing or replacing it. Pumping the tank will cost about $250 to $600, depending on local labor costs, tank size, how far you are from a dumping ground, and dump fees. Removing and replacing a 1,000-gallon concrete tank will cost approx. $5,500.

Septic Tank Baffle Replacement Cost

It will cost $23 to $44 for the septic tank baffle part—this directs wastewater through the septic tank properly without disturbing the natural settling of the tanks’ scum layer.

Septic Tank Lid Replacement Cost

Metal tank lids will typically rust over time, and concrete covers can crack and will need to be replaced. A septic tank lid costs about $30 to $65 to replace not including professional installation.

New Septic Tank Installation Showing Buried Tank With Two Tank Lids

Septic Tank Filter Replacement

The most common repair you will perform on your septic system is filter replacement. Expect to pay around $230 to $280 to install a quality filter for your septic tank.

Cost to Install A Septic Riser

Installing a septic tank riser will give you access to your septic tank at ground level by adding a piped shaft from the top of the tank to the ground level. A riser will cost you about $300 to $400 installed—very much worth it to give maintenance crew easy access should it needs repairs or maintenance. A polyethylene riser will be lightweight and easy to remove, while a concrete riser can be cumbersome and difficult to install, and can crack. Newer tanks usually come with the riser already attached, but old tanks can be fitted with one.

  • Septic Tank Riser Installation Cost – Installation or the labor cost to install your riser will be approx. $200. Add that to the price of the riser (below).
  • Plastic Septic Tank Riser Cost – A plastic septic tank riser with an adapter ring and lid costs approx. $75 to $155, with the highest-rated riser kits by Aero-Stream costing $195–$325, available from 7”–51” tall.
  • Concrete Septic Riser Cost – Concrete risers come in varying lengths with square, rectangular, or round holes and walls that are 3”–4” thick. Prices are only available from manufacturers upon request.

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Septic Tank Price for Mobile Home

The average prices to install a septic tank for a mobile home is approx. $3,900, with most homeowners spending between $3,300 and $5,000. Expect to pay $9,500 for a septic system with two alternating pumps. Local building codes will dictate exactly how the system should be designed.

Concrete Septic Tank Being Installed On Ranch House

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.

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Frequently Asked Questions

How Many Years Does A Septic System Last?

A newly bought and installed septic system should last for about 40 years if the tank quality and installation process are good and the system is maintained regularly.

How Often Does A Septic Tank Need To Be Pumped?

While septic tank systems vary in capacity to suit the wastewater output from your home, they are designed to be big enough to store roughly three years’ worth of sludge before needing to be emptied.

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Labor Costs & Hiring a Septic Company

The average labor fees for professional septic system installation ranges from $1,500 to $3,000 depending on the size, and the materials (weight) of the tank. On an hourly basis for materials, insurance, and equipment rental and you’re looking at about $160/hour.

To work toward making a final selection on your contractor, create a list that contains the 3 to 5 home improvement contractors who match most of the requirements on your checklist. Try to find as many as possible who match the following criteria:

  • Have technicians with years of on-the-job experience
  • Offer a guarantee or warranty
  • Are A+ rated with the Better Business Bureau
  • Are bonded and insured
  • Have multiple great reviews online
  • Follow all local municipality laws and building codes and acquire the right permits before work begins.

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