Concrete Septic Tanks
A complete guide to concrete septic tanks — sizes, cost, how they compare to plastic and fiberglass, and what to know before installing one.
What Is a Concrete Septic Tank?
A concrete septic tank is a wastewater holding and treatment tank made from precast reinforced concrete. It is the most traditional and widely used type of septic tank in the United States, and most local health departments accept concrete tanks without question.
Concrete tanks are manufactured at a precast facility, delivered on a flatbed truck, and lowered into the excavated hole using a crane or boom truck. They come in single-compartment and two-compartment designs, with most modern codes requiring two compartments for better waste separation.
Their heavy weight (4,000 to 12,000+ pounds depending on size) is both an advantage — they resist shifting and floating in saturated soil — and a disadvantage, since installation requires heavy equipment and adds to the cost.
Concrete Septic Tank Sizes
Concrete septic tanks are available in standard sizes from 500 to 2,000+ gallons. The size you need depends on your home's bedroom count and local code requirements:
| Tank Size | Bedrooms | Approx. Weight | Tank Cost |
|---|---|---|---|
| 500 gallon | 1 bedroom | 4,000 lbs | $700–$900 |
| 750 gallon | 2 bedrooms | 5,500 lbs | $800–$1,100 |
| 1,000 gallon | 3 bedrooms | 7,000 lbs | $900–$1,400 |
| 1,250 gallon | 4 bedrooms | 8,500 lbs | $1,100–$1,600 |
| 1,500 gallon | 4–5 bedrooms | 10,000 lbs | $1,300–$1,800 |
| 2,000 gallon | 5+ bedrooms | 12,000+ lbs | $1,600–$2,200 |
Tank-only prices. Does not include excavation, delivery, or installation. See the complete sizing guide or use our size calculator.
How Much Does a Concrete Septic Tank Cost?
The total cost of a concrete septic tank includes the tank itself, delivery, excavation, crane rental, and labor. Here is a breakdown for a standard 1,000-gallon installation:
| Cost Component | Price Range |
|---|---|
| Concrete tank (1,000 gal) | $900–$1,400 |
| Delivery (within 30 miles) | $150–$400 |
| Excavation | $500–$1,500 |
| Crane / boom truck | $200–$500 |
| Installation labor | $500–$1,200 |
| Permits and inspection | $200–$500 |
Total installed cost: Expect to pay $2,500 to $5,500 for a complete concrete septic tank installation, or $3,000 to $6,000+ for larger tanks. This does not include the drain field, which is a separate cost. See our full installation cost guide.
Pros and Cons of Concrete Septic Tanks
Advantages
Disadvantages
Concrete vs Plastic vs Fiberglass
Choosing a septic tank material is one of the most important decisions during installation. Here is how concrete stacks up against the alternatives:
| Feature | Concrete | Plastic | Fiberglass |
|---|---|---|---|
| Cost (1,000 gal tank) | $900–$1,400 | $500–$1,000 | $1,200–$2,000 |
| Lifespan | 40–50+ years | 30–40 years | 40–50 years |
| Weight | 7,000+ lbs | 200–400 lbs | 200–350 lbs |
| Floating risk | Very low | High in wet soil | Moderate |
| Crack resistance | Moderate | Excellent | Good |
| Corrosion resistance | Low (H2S damage) | Excellent | Excellent |
| Installation ease | Requires crane | Manual / light equipment | Manual / light equipment |
| Code acceptance | Universal | Most areas | Most areas |
Concrete Septic Tank Lids and Risers
Concrete septic tanks come with heavy concrete lids that sit on top of the tank body. These lids weigh 50 to 200+ pounds each and are sealed with a tar or mastic sealant. Over time, these seals can deteriorate and allow groundwater infiltration.
If your concrete tank is buried more than a few inches deep, adding a septic tank riser brings the access point to ground level, making future pump outs faster and cheaper. You can use either a concrete or plastic riser on a concrete tank — plastic risers with adapter rings are the most popular retrofit option.
Tip: Have your pumping company inspect the lid and lid seal during each service visit. Cracked or deteriorated lids should be replaced promptly to prevent groundwater from entering the tank and overloading your drain field.
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Frequently Asked Questions
How long does a concrete septic tank last?
A well-built concrete septic tank lasts 40 to 50 years or more with proper maintenance. Some concrete tanks have been in service for over 50 years. The key factors are the quality of the concrete mix, proper installation, regular pumping, and avoiding corrosive chemicals that degrade the concrete over time.
How much does a concrete septic tank cost?
A concrete septic tank costs $700 to $2,000 for the tank alone, depending on size. A 1,000-gallon concrete tank typically costs $800-$1,200. Total installed cost (including excavation, delivery, and labor) ranges from $2,000 to $6,000. Concrete tanks cost more to install than plastic due to their weight requiring heavy equipment.
Are concrete septic tanks better than plastic?
Concrete tanks are more durable, heavier (less likely to shift or float), and accepted in all jurisdictions. However, they cost more, are harder to install, and can crack or corrode over time. Plastic tanks are lighter, cheaper, and corrosion-resistant but may shift in wet soil. The best choice depends on your soil type, water table, and local code requirements.
Can a concrete septic tank crack?
Yes, concrete septic tanks can develop cracks over time due to ground shifting, heavy vehicle traffic above the tank, tree root pressure, or corrosion from hydrogen sulfide gas inside the tank. Hairline cracks are common and usually not serious, but structural cracks can allow groundwater to infiltrate or sewage to leak out, requiring professional repair or replacement.
What size concrete septic tank do I need?
Septic tank size is based on the number of bedrooms in your home, not the number of residents. A 2-bedroom home needs at least a 750-gallon tank, 3 bedrooms need 1,000 gallons, 4 bedrooms need 1,250 gallons, and 5+ bedrooms need 1,500 gallons or more. Local codes may require larger minimums.