About Septic Tank Calculator

Septic Tank Calculator is a free sizing and cost tool for a household septic system. You set bedrooms, occupants, soil and system type. It returns the tank gallons, the drainfield area and a line-item install price, each one tagged with the table it came from. The default is the common US baseline used by the EPA onsite manual and most state codes. A state override appears only after someone has read that state's code.

It is for a homeowner, a buyer or anyone trying to read a bid. It is not a permit, not an inspection and not a substitute for a licensed designer. Counties size against their own tables, their own setbacks and a soil evaluation of the actual yard. Use the numbers to walk into that conversation with a figure, not to skip it.

The calculators run in your browser. Bedroom count, occupancy and perc rate never leave the page. There is no account and nothing is stored. The site is free because the tables are public and the running cost of a static page is nothing. If a number looks wrong, email hello@septictankcalculator.com and say which input produced it.

Septic Tank Calculator is built by Madhu Kinnera and published by Marava Tech. Corrections to a table, a citation or a cost range are welcome.

Contact

Questions or feedback? Email hello@septictankcalculator.com.