In any digging project, if you hit something underground, chances are it will not be buried treasure. Underground utility strikes are dangerous and costly, but luckily are almost always avoidable. With proper planning and preparation, you can locate potential underground hazards before they become a problem.
Different types of equipment are used for different types of jobs. The best equipment for locating a utility line depends mainly on the material that the line is made of (metal, PVC, plastic, etc.) and the ground material or building material that the device must penetrate for accurate mapping.
How to Locate Underground PVC Pipes
PVC, or polyvinyl chloride, can be tricky to find because there is little or no metal in the pipe system, rendering a metal detector useless. Today, the best tool for the job is ground penetrating radar (GPR) as it accurately maps metal and PVC pipes. Traditional pipe locators use electricity and magnets to locate underground pipes.
Hand-held pipe finding tools can be effective for locating PVC pipes, but only if the PVC system was fitted with a tracing wire during installation. Further, handheld pipe finders typically vary widely in price and quality; the most inexpensive start at $300, ranging all the way to $3,500. Underground pipe locators also come with a learning curve and can be challenging to use correctly at first without training.
Fiberglass probing wires can be fed into the pipe system retroactively but are only a temporary solution. Further, probing wires are only appropriate for systems that can be fully shut down and disconnected — the wire must be physically fed into the system, then scanned for using a traditional pipe locator.
When looking for completely unmarked PVC pipe, there are essentially two options: to manually probe or to call a professional. Hand probing is the process of repeatedly pushing a metal rod into the ground to physically feel for the buried PVC pipe. Soil probe rods themselves are relatively inexpensive, but the process can be extremely time consuming…and frustrating.
Acoustic pipe locating is another method often used by professionals; however, it is only suitable for locating already damaged or leaking pipelines. Locating buried PVC pipe before it becomes a problem saves time and money. The easiest and most accurate way to find all your unmarked PVC pipes is with the help of an underground utility mapping professional with 3D mapping capabilities.
How to Locate Underground Sinkholes Before They Collapse
A sinkhole forms when rock below the surface of the soil is dissolved by groundwater over time. The slowly growing gap left behind by the eroded rock then traps rainwater and melted snow draining through the surface soil. Water accumulates until the ground weakens and suddenly caves in. The hole left behind can range from a few feet to acres, from less than one to more than 100 feet deep, according to the USGS.
Sinkholes are epically dangerous because they form slowly and often go unnoticed as the surface of the ground does not change much visually. A digging project of any scope can trigger a sinkhole collapse, and it is significantly less work to reenforce a forming sinkhole before it collapses.
Always be on the lookout for common signs a structure may be on top of a sinkhole. If you notice any visual signs of a sinkhole, or are in an area of the US prone to sinkholes, the only sure way to determine if it is safe to dig is to survey the property with ground penetrating radar.
How to Locate Underground Water Lines
Private utility locators can help you find underground water lines that are buried on a property. This involves specialized equipment. They use both ground penetrating radar and electromagnetic conductivity (EM) devices.
How to Locate Underground Drainage Pipes
The method for locating buried drainage pipes depends on what material the pipe is made of; most drainage pipes these days are made of PVC. In that case, see the instructions above for finding PVC pipes. Older homes, built before the 1960s, may have drainage pipes made of steel, iron, or copper. Underground metal pipes can be mapped using either ferromagnetic detection (FM) or GPR.
Related Article: Thermal Imaging for Underground Utility Location.
Public vs. Private Utilities
The first step to planning your digging project is understanding the difference between public and private utilities. Call 811 is a free underground utility locating service, but they only locate government infrastructure like public water, sewage, electricity and natural gas lines. Private utility locators are necessary to locate anything else that may lie beneath the surface of the soil on private, residential, commercial properties.
Most are unaware of all the underground hazards below their properties. Overtime obsolete lines replaced by previous owners are commonly left buried and otherwise undetectable from the surface. It is difficult to find something if you do not know you are looking for it.
Check for these common underground private utilities possibly hidden on your property:
- Electricity for exterior and landscape lighting
- Well water systems
- Propane or natural gas lines for heated pools
- Septic pipes and tanks
- Sprinkler systems and water features
- Power for a detached garage
- Storm drains.
Safer with SoftDig
At SoftDig, our priority is ensuring all job no matter the scope is safe, accurate and efficient. Thorough planning, diligent safety practices and consistent compliance are vital to a successful project, no matter the scope. We are here to help you and your team find underground obstacles before they become hazards to you and your community.
Helping our customers meet their goals since 1959, we stay at the front of our industry to ensure the highest safety and accuracy on every project. Contact our team today to learn more about our utility mapping services.