Septic Tank Size Calculator
Calculate the right septic tank size for your home.
Bedrooms determine expected occupancy
If known, otherwise calculated from bedrooms
Tank Size = Max(Occupants × Daily Gallons × 2 days, Minimum Code Size by Bedrooms)
Example: 3-bedroom home with 4 people = 750-gallon minimum septic tank. Recommended: 1,000-gallon tank for future-proofing and efficiency
How is septic tank size determined?
Tank size is based on number of bedrooms (determines max occupancy), daily water usage, and local code requirements. Most codes require minimum sizes based on bedrooms.
How often should I pump my septic tank?
Typically every 3-5 years, depending on tank size, household size, and water usage. More occupants or heavy water use requires more frequent pumping.
What happens if my septic tank is too small?
An undersized tank won't allow proper settling of solids, leading to drain field clogging, backups, and potential system failure requiring expensive repairs.
📐 Formula
Tank Size = Max(Occupants × Daily Gallons × 2 days, Minimum Code Size by Bedrooms)
📝 Example Calculation
Example: 3-bedroom home with 4 people = 750-gallon minimum septic tank. Recommended: 1,000-gallon tank for future-proofing and efficiency
❓ Frequently Asked Questions
How is septic tank size determined?▼
Tank size is based on number of bedrooms (determines max occupancy), daily water usage, and local code requirements. Most codes require minimum sizes based on bedrooms.
How often should I pump my septic tank?▼
Typically every 3-5 years, depending on tank size, household size, and water usage. More occupants or heavy water use requires more frequent pumping.
What happens if my septic tank is too small?▼
An undersized tank won't allow proper settling of solids, leading to drain field clogging, backups, and potential system failure requiring expensive repairs.