Septic Tank Sizing Calculator
Size septic systems per typical code requirements
Drain Field Sizing
Septic System Results
Minimum Tank Size
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Recommended Size
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Daily Flow Estimate
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Retention Time
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Drain Field
Required Area
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Trench Length (2' wide)
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Minimum Tank Sizes (Typical Code)
| Bedrooms | Min Tank (gal) | Design Flow |
|---|---|---|
| 1-2 | 750 | 300 gpd |
| 3 | 1000 | 450 gpd |
| 4 | 1250 | 600 gpd |
| 5 | 1500 | 750 gpd |
| 6 | 1750 | 900 gpd |
Septic System Guidelines
Tank Requirements
- Minimum 750 gallons (most codes)
- Two compartments recommended
- 24-48 hour retention time
- Access risers to grade
- Effluent filter on outlet
Drain Field
- Size based on perc test
- Minimum 100% reserve area
- Trenches 18-36" wide
- 6-12" gravel below pipe
- Distribution box or D-box
Setbacks (Typical)
- 10' from building
- 50-100' from well
- 10' from property line
- 25' from streams/ponds
- Check local requirements