How To Locate Septic Tank Cleanout. If you have a septic system, then the clean out should be between the house and the septic tank. The drain line should be a maximum depth of 2 feet or shallower.
Find that same location outside and mark it. The cap covers a cleanout pipe to prevent wastewater, rain, dust, and pests from entering the sewer line. Once you’ve found the direction, look for any high or low spots in the yard that could indicate where your septic tank could be.
Usually, the cap of the cleanout will be found anywhere up to three feet from the foundation, so have a good look around your house!
Continue digging until you locate a seam in the tank lid, then remove enough dirt to expose the entire seam. One way to find it is to visualize a line from a floor drain running out toward the municipal sewer lines, which usually lie beneath the street. This is true whether the home has a septic tank or connects with the county sewerage system. While most cleanouts are located outside the home, some (especially in older homes) are located inside.