You can expect an average septic tank weight to be about 273 pounds (124 kg) for plastic tanks, 395 lbs (179 kg) for fiberglass tanks, and about 10,218 lbs (4,635 kg) for concrete tanks.
How much a septic tank weighs will vary depending on its use and type. Plastic septic tanks tend to weigh between 80 to 500 lbs, fiberglass tanks weigh between 300 to 500 lbs, while precast concrete septic tanks can weigh well above 8,000 lbs. Size and weights will also vary depending on if the tank is designed for personal and home use, or commercial use.
If you plan on hauling your septic tank, make sure to check your vehicle’s towing capacity. This can be found in your owner’s manual or the manufacturer’s website as your gross vehicle weight rating (GVWR).
7 Example Septic Tank Weights
The following chart features example septic tank weights of specific models ranging from the lightest to the heaviest used in the field. Additional details can be found on the manufacturer’s websites. Here’s the septic tank weight chart:
| Septic Tank Model | Weight |
| 200 Gallon Plastic Septic Pump Tank | 80 lbs (36 kg) |
| 750 Gallon 2 Compartment Plastic Septic Tank | 298 lbs (135 kg) |
| 750 Gallon 2 Compartment Fiberglass Septic Tank | 320 lbs (145 kg) |
| 1250 Gallon Norwesco Plastic Bruiser Tank | 443 lbs (201 kg) |
| 1500 Gallon 2 Compartment Fiberglass Septic Tank | 470 lbs (213 kg) |
| 1000 Gallon Concrete Septic Tank | 8,765 lbs (3,976 kg) |
| 1500 Gallon 2 Compartment Concrete Septic Tank | 11,670 lbs (5,293 kg) |
Sources: Tank Depot, Loomis Tank Centers, Shea Concrete
To Conclude
Septic tanks provide a great method of wastewater treatment. Each make, model, and size comes along with its own weight based on use and if any other modifications are made. The key factors to consider the weight of a septic tank come down to:
- Length and size
- Construction material
- Number of gallons
- Number of compartments
It’s important to know the correct weight when looking to tow and transport a septic tank. If you’re unsure and want specific weights, you can always check the manufacture’s website or go to a local cat scale to get a more accurate weight.