A septic tank costs between $500 and $2,500, depending on what size tank you need. An entire septic system costs between $3,601 and $12,474, with a national average price of just over $8,000.
Factors that affect the cost of a septic tank include tank size and materials. Homeowners can keep costs down by doing the landscape prep, buying the materials themselves and scheduling tank installation during the off-season.
How much does a septic tank cost?
If you already have a septic system in place and only need to replace the tank, your final costs will depend on the tank size and materials.
Tank size
Here’s what you might expect to pay for just the tank itself, based on tank size:
| Tank Size | Price Range |
|---|---|
| 500 gallons (suitable for a one-bedroom house) | $500 to $900. |
| 750 gallons (suitable for a two-bedroom house) | $700 to $1,200. |
| 1,000 gallons (suitable for a three- or four-bedroom house) | $900 to $1,500. |
| 1,200 gallons (suitable for a five- or six-bedroom house) | $1,200 to $1,600. |
| 1,500 gallons (suitable for a six- or seven-bedroom house) | $1,500 to $2,500. |
Materials
The material your septic tank is made of affects its price. For example:
| Material | Average Price Range |
|---|---|
| Concrete | $700 to $2,000. |
| Fiberglass | $1,200 to $2,000. |
| Plastic | $500 to $2,000. |
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How much does it cost to replace an entire septic system?
If your septic system is damaged or past its life expectancy, you may need to replace the entire system, not just the tank. Full septic system costs depend on the system type and the labor, permits and required testing.
System type
- Anaerobic: $3,000 to $8,000.
- Aerobic: $10,000 to $20,000.
- Alternative systems: $5,000 to $20,000. If a traditional septic system won’t work on your property, you may need an alternative system. Alternatives include a mound, drip, chamber, sand filter, evapotranspiration or built wetland setup.
Other factors that affect the cost of a new septic system
Labor: 50% to 70% of the total job price. If you need excavation to install your septic system, this will likely add an extra $1,500 to $6,300 to labor costs.
Land survey: $330 to $900 from a licensed land surveyor.
Permit: $450 to $2,300. Laws vary by location.
Percolation testing: $700 to $2,000. This test checks how your soil absorbs water and helps determine which type of septic system is best for your property.
Leach field installation: $500 to $12,000. A leach field (also known as a drain field) is a type of trench that transports wastewater back to the soil.
What is the life expectancy of a septic tank?
On average, septic systems last 15 to 40 years. With proper care and routine maintenance, they may last even longer. Here are a few tips that will help you keep your septic system working properly for as long as possible:
- Don’t put items into your sink or toilet that could clog your septic system. These items include feminine hygiene products, baby wipes, diapers, coffee grounds, cigarettes, cat litter and grease.
- Don’t put items that could damage or “kill” your septic system into your sink or toilet. These items include gasoline, household chemicals, oil, paint, antifreeze, pesticides or large quantities of household detergents and soaps.
- Don’t overuse water. When you conserve water, your septic system won’t have to work so hard. It also helps to opt for high-efficiency plumbing appliances, repair household plumbing leaks and stagger the use of appliances to avoid straining your septic system.
- Don’t use a garbage disposal unless absolutely necessary. Reducing or eliminating garbage disposal use helps reduce the volume of damaging grease, fats and other solids that get into your system.
- Protect your leach field. Plant trees away from the field, as roots can clog up the field and cause system failure. It’s also wise not to put anything heavier than a lawnmower on your field, and to direct excess water (from drains, heavy rainfall and irrigation) away from the leach field area.
What does it cost to maintain a septic tank?
Plan to have your septic system inspected and your tank pumped out about every three to five years, or as recommended by your municipality or service provider. A professional inspection will tell you when pumping is necessary. Alternative systems need more frequent inspection and service.
This scheduled routine maintenance should cost between $250 to $500. This might feel like a lot of money, but it can prevent costly repairs that could run you tens of thousands of dollars.
7 ways to save money on the cost of a septic tank
- Compare multiple quotes from trusted, reputable contractors.
- Purchase materials yourself instead of through the contractor. This helps avoid price markups.
- Gather your own soil samples for testing.
- If you have the required skills, prepare your land yourself instead of hiring a professional. This work might include backfilling and other prep work.
- Confirm code compliance and get the necessary permits yourself.
- Arrange to have work done during the off-season, when you may be able to get discounts and lower rates.
- If you need a new septic tank due to damage from a specific event, find out if your homeowner's insurance policy might cover some or all of your tank replacement costs.
What Reddit users say about septic tank replacement
Reddit is an online forum where users share their thoughts in “threads” on various topics. The popular site includes plenty of discussion on financial subjects like home improvement, so we sifted through Reddit forums to get a pulse check on how users feel about septic tank replacement. People post anonymously, so we cannot confirm their individual experiences or circumstances.
Reddit users who have replaced septic tanks say that it’s fine to just replace the tank when it stops working. You don't have to replace the entire leach field as long as the field is still operating properly. To keep septic tanks in good condition, users suggest having the tank pumped every two to three years, and using RID-X, a treatment solution, to keep the tank clean between pumpings. Many users also say that their septic tanks have lasted as long as 40 or 50 years with proper maintenance.
Frequently asked questions
Can I DIY a septic tank installation?
Although DIY septic tank installation is allowed in some states, this isn’t a job for inexperienced homeowners. The job involves working around human waste, which is a biohazard. It also requires heavy equipment. If you do this work improperly, there are a lot of risks, including:
- Soil and water contamination.
- Risks to public health.
- Improper treatment of sewage.
- Sewage backup or burst pipes.
- Lower property value.
- Being fined by your local government.
- The expense of repairing or reinstalling your system.
What’s the difference between aerobic and anaerobic septic systems?
Anaerobic means “not needing oxygen”. These systems use strains of bacteria that don’t need oxygen to break down human waste. Anaerobic systems don’t need any chemicals or electricity to operate, and are the most common type of septic system. They’re also usually the most affordable option.
Aerobic systems have oxygen pumped into the septic tank. This activates strains of bacteria that do need oxygen to feed on solid human waste. These systems are more efficient but also more costly. They also require electric power to run, so if you have a power outage, you’ll need a generator to keep them operating.
Does home warranty cover septic tanks?
Standard home warranty plans don't automatically cover septic systems, but most home warranties allow you to buy additional coverage. Septic pumps are a common add-on, and some plans even include annual tank pumping. However, it's rare for a full tank replacement to be covered.
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