Search tools and charts

Septic planning toolkit

Septic Calculators

Start with the question you need to answer. Each calculator explains its assumptions, limits, and primary sources.

Choose a septic calculator

Use one tool at a time, then carry the result into the next planning step.

Planning tools, not permit designs

Tank and drainfield requirements vary by jurisdiction, soil, use, and system type. Confirm final values with the permitting authority and a qualified professional.