Home & work

Make a better-informed decision.

Understand your county’s radon context and trace a federal salary rate to its published table.

Radon zones

Understand the county behind a ZIP area.

Find an official FEMA map and read its zones with care.

Grade, step and locality, clearly explained.

Estimate appliance use and compare published state averages.

A county-level potential category cannot measure the air inside a home.

The lookup uses Census geography, with boundaries and relationships that need explanation.

Choose the correct table before comparing grade and step.

Trace a calculator result to the exact OPM row and column.