Hammer CalculatorCalculators / Plumbing / Septic Tank Sizing Calculator
Septic Tank Sizing Calculator
Estimate the right septic tank size and drain field length for your property. Compare tank materials and costs based on your household size, water usage, and soil percolation rate.
Septic Tank Sizing Calculator
Garbage Disposal
Fixture Efficiency
Pricing (edit to match local rates)
Daily Flow
300 gal/day
4 people @ 75 gal/day
Recommended Tank
1,000 gal
IRC min: 1,000 gal (3 BR)
Drain Field
200 lin ft
600 sq ft @ 0.5 perc rate
Best Total Cost
$8,500.00
Concrete tank + drain field
| Purchase Option | Quantity | Est. Cost |
|---|---|---|
| ConcreteBest value | 1,000 gal tank | $8,500.00 |
| Fiberglass | 1,000 gal tank | $9,200.00 |
| Polyethylene (Plastic) | 1,000 gal tank | $8,800.00 |
Cheapest option: Concrete at $8,500.00The IRC minimum of 1,000 gallons for 3 bedrooms is sufficient for your estimated daily flow of 300 gallons. The drain field needs approximately 200 linear feet of trench based on your soil perc rate.
Concrete Tank AdvantagesConcrete tanks are the most common choice — they resist buoyancy in high water tables, accept risers easily, and typically last 40+ years. However, they require heavy equipment for installation and can crack if soil shifts. Ensure the installer uses a watertight sealant on all joints.
This is a planning estimate only. Actual septic system sizing must comply with local health department regulations, which may differ from IRC minimums. A site-specific perc test and soil evaluation by a licensed septic designer are required before installation.