Septic Tank Size by Bedrooms
IPC table: 750-1500 gal by bedroom count. State codes vary.
Result
Required tank size
1000 gal
3-bedroom IPC base + no extras.
- Bedrooms3
- IPC base1000 gal
- Garbage disposal?no
- Final tank size1000 gal
- Pumping interval3-5 years (typical)
Step-by-step
- IPC table for 3 bedrooms: 1000 gal.
- No additions → 1000.
How to use this calculator
- Enter bedrooms.
- Toggle garbage disposal.
- Verify with local building dept.
About this calculator
IPC standard septic tank sizing by bedroom count: 1-2 BR = 750 gal, 3 BR = 1000 gal, 4 BR = 1250, 5-6 BR = 1500. State codes may require larger. Garbage disposal adds 250 gal (more solids). Tank size determines retention time (typically 24-48 hours) — longer = more solid settling, less burden on drain field. Pump every 3-5 years (don't skip — saves drain field).
Frequently asked
Bedrooms = max possible occupancy. State sizing is conservative for resale (next family may have more people).
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