Septic Tank Calculator
Septic Tank Size Calculator
Sizing a septic tank starts with how much wastewater the property produces each day. Enter the number of bedrooms in the home, or the daily flow in gallons if you already know it, and the calculator returns a recommended tank capacity in gallons.
The estimate uses 150 gallons per day per bedroom and a two and a half day retention period, which is the sizing basis most residential codes are built around. Your county may require more, and some jurisdictions size on fixture count or occupancy instead of bedrooms. Confirm the requirement with your local health department or installer before you buy.
Results above 1,500 gallons are shown as 1,500, which is the largest single tank in our standard range. Larger applications are usually handled with multiple tanks in series, and our team can size that for you.
If you already know the capacity you need, you can browse the full septic tank range directly.
Important: This is an estimate only. Always verify requirements with your local installer or authority having jurisdiction before purchasing. For applications requiring over 1500 gallons, please contact our sales representatives for a solution.