How to Locate Underground Sewer Pipes

Written by gail delaney | 13/05/2017
How to Locate Underground Sewer Pipes
(Hemera Technologies/ Images)

Sewer lines are wonderful when they work properly, but if you need to replace or repair your sewer line, then you need to know where the line is located. Sewer lines are hidden below the ground, rarely seen. If you just moved on to the property, or if you are building a new house, you need to locate your underground sewer lines by knowing where to find the information you need.

Find the sewer vent on top of your roof and then find the outside clean-out line. Line up a straight line from the sewer vent to the clean-out line and out to the alley where your line meets the city's line.

Talk to the city maintenance person. He can tell you where your line runs.

Go to the sewer department in your city. They should have an infrastructure map that will help you. This map will tell you how far from your property the city's mains are and where it is located. It will also tell you the depth of the lateral service connection.

Send a camera down the sewer line. You will need to contact a plumber to do this for you as they have the necessary equipment. The small camera will show you where the sewer line is located. Some plumbers also use radar.

Douse to find the sewer line, by using welding rods or coat hangers that have been straightened out. Bend one end of each rod at a 90 degree angle to make a handle. Hold the rods by the handle so the rods point out in front of you and then slowly walk around the property where you believe the sewer line is located. When the rods cross, you have located the sewer line.


  • Willow rods also work for dousing instead of welding rods.

Tips and Warnings

  • Willow rods also work for dousing instead of welding rods.

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