Tools and calculators

Each tool explains how it works, where its numbers come from and what it can't tell you. Use the results for planning, and let a professional's measurement or your local rules decide.

Septic symptom checker Tick what you can see or smell to learn how urgent a septic problem may be, and what to do first. Based on EPA warning signs.
Septic tank size calculator Compare minimum septic tank sizes by bedroom count in four published state rules, with the disposal adjustments and rule sources shown.
State septic program contacts Find the official septic program page for all 50 states, with phone numbers checked against state websites where they publish one.
Drain field size calculator Estimate drain field absorption area from bedrooms and soil type, using published flow and loading rates. See the formula and its limits.
Septic system cost estimator See published installed-cost ranges for each septic system type, side by side from two national guides, with the disagreements left in view.
Septic checklist for home buyers A printable checklist of what to ask and check before buying a home with a septic system. Your progress stays saved in your browser.
Septic tank pumping calculator Estimate how many years to leave between septic tank pumpings, based on tank size and household size. Uses a published Extension table, with its limits shown.