Found PVC Pipe in Fence Post Hole? How to Identify Mystery Underground Objects in 2026
PVC Pipe in Fence Post Hole? How to Identify Mystery Underground Objects in 2026" loading="eager">Photo by Sergei Starostin / Pexels
Understanding Underground Obstacles: The Mystery Pipe Discovery
When you're digging fence post holes, you expect to hit rocks or roots. What you don't expect is discovering mysterious pipe-like objects buried in your yard. One homeowner's quest to identify an unknown underground object sparked a fascinating investigation that many DIYers have faced themselves.
This common situation reveals an important truth: many properties have hidden utilities, old infrastructure, or natural materials buried beneath the surface. Whether you're dealing with abandoned PVC pipes, bone deposits, or other underground objects, knowing how to safely identify and handle them can save you time, money, and potential safety hazards.
Testing Methods to Identify Underground Objects
Before you assume anything about what's buried in your yard, proper testing is essential. The homeowner in this scenario used several practical methods that any DIYer can replicate.
The Scrape Test
One of the first identification methods is the scrape test. Using a sharp tool like a box cutter, you can attempt to shave material from the object's surface. Results vary significantly depending on what you've found:
- PVC pipe will show white or colored scratches and material removal
- Bone will be extremely hard and resist scraping almost completely
- Metal will show metallic coloration or scratches depending on the material
- Root material will compress slightly or splinter
In the case of our mysterious object, nearly nothing came off when scraped, suggesting extremely hard material like bone or metal oxide coating.
The Magnetic Test
A simple magnet or magnetic detector can eliminate ferrous metals from consideration. If your object shows no magnetic attraction, you can rule out iron, steel, and most common metals. This is particularly useful because many old utilities used metal piping, which would respond to magnetic testing.
The Electrical Test
Using a live circuit detector pen helps identify active electrical lines or conductive metals. These tools detect electromagnetic fields and electrical current. A zero result suggests the object isn't an active power line, though it could still be old copper piping or non-ferrous metal.
Common Underground Objects You Might Encounter
| Object Type | Magnetic Response | Scrape Result | Electrical Detection | Hardness |
|---|---|---|---|---|
| PVC Pipe | None | Scratches easily | None | Soft to medium |
| Metal Pipe (Steel) | Strong | Metal marks visible | Possible | Very hard |
| Bone | None | Nearly impossible | None | Extremely hard |
| Copper/Aluminum | None | Metal scratches | Conductive | Hard but soft than steel |
| Tree Root | None | Splinters/compresses | None | Medium, varies |
| Concrete/Rebar | Possible (rebar) | Very hard | Possible | Extremely hard |
When to Call Professionals and Authorities
The homeowner's decision to contact the police non-emergency line shows good judgment. When you discover unusual objects, especially those that might be bone or other concerning materials, it's worth checking with authorities first.
Who to Contact for Different Scenarios
- Utility lines: Call 811 (Call Before You Dig) before any digging project
- Active electrical or gas lines: Contact your utility company immediately
- Suspected human remains: Contact local police non-emergency line first
- Old metal or pipe: Contact local waste management for proper disposal guidance
- Unknown substances: Document with photos and consult with professionals
Most authorities won't be interested in old bones from animals or archaeological artifacts unless there are specific concerns. However, it's always better to report and be cleared than to ignore potential issues.
Practical Solutions for Fence Post Installation
Once you've identified the object and determined it's safe to work around, you need a practical solution. The original poster found a creative workaround rather than removing the obstruction entirely.
Working Around Underground Obstacles
Several strategies exist for fence installation when you encounter persistent obstacles:
- Adjust the fence line slightly to avoid the object entirely
- Use a post auger or fence post driver with extended reach if possible
- Dig around the object carefully and work the post hole past it
- Consult with a professional fence installer who has experience with problem properties
- Consider the fence design—angled posts or different foundation methods might work better
The most effective solution often depends on the size and nature of the obstruction. An object that's just a few inches down might be worked around easily, while something deeper in your planned post hole might require more creative solutions.
Prevention Tips for Future Digging Projects
Once you've dealt with one underground mystery, you'll want to prevent surprises on future projects.
Before You Dig Anywhere on Your Property
Always call 811 or your local utility locating service before any digging. They'll mark underground utilities for free, helping you avoid:
- Electrical lines and cables
- Gas lines
- Water mains and irrigation
- Sewer and septic systems
- Telecommunications cables
Beyond utilities, research your property's history. Old properties might have abandoned wells, septic systems, or other structures you should know about before digging.
Key Takeaways
- Use multiple testing methods to identify underground objects: scraping, magnetic testing, and electrical detection
- Extremely hard materials that resist scraping are likely bone or metal, not PVC
- Contact authorities when discovering potentially concerning objects, though most will be harmless
- Creative workarounds often solve fence post problems without removing the obstruction
- Always call 811 before digging and research your property's history
- When in doubt, consult professionals rather than risk utility damage
Frequently Asked Questions
How can I tell if I've found PVC pipe versus bone?
PVC pipe will scratch relatively easily with a sharp tool, showing white material underneath colored exterior. Bone is extremely hard and resists scraping almost completely. Additionally, PVC is non-magnetic and won't conduct electricity, but neither will most bones. The primary difference is workability—PVC yields to tools while bone is nearly impossible to mark.
Is it safe to dig around mysterious underground objects?
It depends entirely on what the object is. Always call 811 before digging to have utilities marked. If you discover something unusual, test it carefully with the methods described, take photos, and consult with professionals if you're uncertain. Most objects encountered are harmless, but caution is warranted until you've identified them properly.
What should I do if I find what looks like bone?
Contact your local police non-emergency line with photos and location information. Most will quickly determine whether it's animal bone or something requiring further investigation. Animal bones are common in yards, especially older properties, and authorities are accustomed to handling these reports.