Damages to buried infrastructure in North America are on the rise. Every year, Common Ground Alliance releases a comprehensive report based on its Damage Information Reporting Tool (DIRT). The most recent DIRT Report indicates that total damages increased 4.5% year-over-year to 532,000. The societal costs of damages to buried utilities in the U.S. is estimated at $30 billion for the year, which includes both direct costs, like facility repair, and indirect costs, such as property damage, medical bills and businesses being unable to operate.

Suffice to say, excavation can be a dangerous and expensive undertaking without employing the proper practices to mitigate the risk of coming in contact with underground utilities and infrastructure. From hitting a water main to ripping out a telecommunications cable—or, worse, puncturing a gas line—there’s no shortage of disruptive and potentially harmful or costly outcomes that can occur as a result of skipping crucial steps in the process. 

With damages trending upward, analysis from the DIRT Report suggests that focusing on damage prevention practices at each step of the safe excavation process is necessary to drive damages down. One of the very first and most fundamental of these practices is test pitting.

Following are some important insights about test pitting as the primary step in any successful excavation project. 

What is test pitting?

Test pitting, also considered another form of potholing, is a minimally invasive procedure to examine subsurface conditions through a series of small excavation holes dug via vacuum excavation or manual shoveling methods. Vacuum excavation is implemented by applying highly pressurized streams of water or air to soften the ground soil and displace it from the test pits through high-suction vacuum equipment. The benefit of vacuum excavation is its ability to move hard or rocky ground without accidentally puncturing or harming the features below.

Either way, test pitting is the safest and most efficient way to start any excavation project, as it enables crew members to identify the precise location of underground infrastructure. Why is this so important at the initial stages of excavation? Because accuracy is key. Even with flags and locators in place, there’s always some risk of running into conflicting utilities or buried lines. And as the data shows, these types of occurrences are more prevalent than ever, with the potential for damages to incur rather dangerous and expensive costs. Mistakes happen, and you can never safely assume that you know the exact location, depth or type of line that exists. 

Test pitting provides an opportunity to access the most precise information on the location of underground infrastructure. That’s the best assurance you can have before beginning an excavation job, which is why this technique is a best practice in the industry.

What steps should be taken to test-pit safely?

As test pitting should be the initial step in any successful excavation project, there are some important tips and precautions to follow in order to do so safely and effectively. 

First, it’s imperative for the contractor of company performing the excavation work to call 8-1-1 before the project even starts. 811 is the federally designated call-before-you-dig phone number. Each state has its own requirements and specifications for digging, so contacting this number is the best way to ensure they’re fulfilled. At least 2-3 days before the work is scheduled to begin, it’s necessary for the company in charge to dial 8-1-1 via phone or make an online request at call811.com. From there, the local center contacts any affected utility operators to mark their buried lines with paint or flags. 

Once this is done, the crew should respect the utility marks and use them as the guide for the duration of the project. Additional pre-excavation safety measures include:

• Consulting any relevant maps or field sketches
• Identifying all services to buildings (e.g., gas meters, cable pedestals, electric cables, water valves, sewer laterals, telephone closures, etc.)
• Scanning for evidence of trench lines or cleared ROWs
• Photographing the job site and taking pictures of locater marks and flags
• Recording all required safety signage
• Erecting fencing or barricades for streets or sidewalks, and placing caution tape where necessary

With the proper utility marks and precautions in place, test pitting is then performed to commence any excavation work. It’s crucial to dig from the sides and never on top of a known utility, using only square, blunt tools. As mentioned, vacuum excavation is particularly safe and effective for this effort. But whether employing vacuum excavation or digging by hand, extreme care is warranted by anyone performing the test pitting.

What’s the tangible value of test pitting?

For crews focused on performing truly safe, successful and cost-effective excavation work, there are tangible advantages to be gained through the process of test pitting. At the top of that list is the unmatched access to the most precise information and insight regarding underground service lines. Obtaining visual verification is as accurate as it gets in terms of understanding the type, horizontal position and depth of buried utility lines (or any existing damage to them). 

Next, there’s the vital hazard mitigation for workers, who face the very real prospect of digging-related injuries or death. Test pitting provides a reliable way to bypass buried infrastructure, thereby protecting the wellbeing of excavation operators. It can even save on project time in the long run. Unexpected damage to subsurface lines are apt to cause significant downtime, and test pitting enables crews to thwart these types of project delays. A shorter timeline also means cost savings, which are amplified when you’re able to prevent the expense of having to repair vital utility lines, accommodate service disruptions or pay noncompliance fines. 

At the end of the day, the benefits of accuracy, safety, efficiency and profitability make test pitting the necessary first step in the excavation process. By partnering with a knowledgeable and experienced construction team who fully understands and prioritizes this step, you’re better positioned to achieve a successful excavation project.

As you research contractors to help with your next excavation project, we invite you to download our free brochure to learn more about our capabilities.