I hit a black pipe digging fence post holes. What should I do now?

Yes, pause the work and leave the pipe exposed for now. Black pipe alone isn’t enough to identify it. It could be part of the septic system or something else, and a dry hole or no obvious smell doesn’t prove it’s abandoned or undamaged.

Call a septic installer or septic-system inspector and ask them to identify the line and check whether it was damaged. A private utility locator may help too. Take clear photos and note where and how deep you found it. Don’t cut, patch, bury, or pour concrete around it until you know what it is.

I wouldn’t set those posts yet, especially the one you’re unsure about. A fence post is easy to move compared with a buried pipe repair. Keep digging gently only if needed to expose enough for a professional to inspect, and avoid levering against the pipe.

When you call, describe the pipe and its location relative to the tank and field. If you think you struck or cracked it, say so plainly. Don’t try to bridge it with another pipe or encase it in concrete as a guess.

Before restarting the fence, get the septic components and any required clearances confirmed. Utility marking often doesn’t cover private septic lines, so ask about a private locate as well as contacting a septic professional. The fence may need to shift once the field layout is clear.