Check your home’s as-built plans, septic permit, or property records
Contact your local health department or building department for septic system records
Look for the sewer line leaving the house, usually from the main bathroom area
Find the cleanout pipe outside the house, then trace the line toward the tank
Search for subtle signs in the yard such as greener grass, slight depressions, or rectangular outlines
Use a metal probe or septic tank locator tool to feel for the tank lid edges
Check common tank locations, usually 10 to 25 feet from the house in the direction of the main drain line
Look near the area between the house and the drain field
Inspect for inspection ports or risers sticking slightly above ground
Ask the previous owner, builder, or septic service company if they have the location
Hire a septic professional to locate the tank with specialized equipment if needed