Check your property records, septic permit, or as-built drawings
Look for the sewer line leaving your house, usually from the basement or lowest bathroom
Find the cleanout pipe or inspection ports near the house
Trace the line direction from the house toward the yard
Look for greener grass, slight depressions, or patches of disturbed soil
Search for vent pipes, access lids, or risers in the yard
Use a metal probe to gently test likely areas
Check near the driveway, front yard, or side yard where tanks are often installed
Contact the previous owner, builder, or local health department
Call a septic professional if the tank cannot be found